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Same but Different? Developmental Pathways to Demonstrative Targeted Attacks — Qualitative Case Analyses of Adolescent and Young Adult Perpetrators of Targeted School Attacks and Jihadi Terrorist Attacks in Germany



Analysis of incidents over the past ten years in Germany reveals that the boundaries between targeted attacks in schools and terrorist attacks are starting to blur. Böckler, Leuschner, Roth, Zick, and Scheithauer (2018) recently presented a set of hypotheses about similarities between the developmental pathways of school attackers and lone actor terrorists. To date there is only a small body of empirical research comparing these two forms of targeted violence in depth. In order to fill this gap, this article presents findings from a qualitative analysis of prosecution files comparing the developmental pathways of German school attackers (N = 7; age range: 13 to 23) and Jihadi attackers (N = 7; age range: 21 to 28 years) who committed their attacks between 2000 and 2013. Using theoretical coding and constant case comparison, the contribution shows that the two phenomena have overlaps in which developmental processes and social mechanisms are similar. Both school attackers and Jihadi attackers frame their act of violence using cultural scripts and perform the attack on a public stage where victims are attacked not on the basis of personal conflicts but because of their symbolic meaning. Taking into account the similarities in the perpetrators’ developmental pathways, the authors propose that it might be more fruitful from an operational perspective to discuss severe target school violence and terrorist attacks under a common concept of demonstrative violence than to artificially assign them to exclusive classes of violence.
International Journal of Developmental Science 12 (2018) 5–24
DOI 10.3233/DEV-180255
IOS Press
Invited Manuscript
Same but Different? Developmental
Pathways to Demonstrative Targeted
Attacks – Qualitative Case Analyses
of Adolescent and Young Adult Perpetrators
of Targeted School Attacks and Jihadi
Terrorist Attacks in Germany
Nils B¨
Institute Psychology and Threat Management, Darmstadt, Germany
Vincenz Leuschner
Berlin School of Economics and Law, Germany
Andreas Zick
Bielefeld University, Germany
Herbert Scheithauer
Freie Universit¨
at Berlin, Germany
Analysis of incidents over the past ten years in Germany reveals that the boundaries between targeted attacks in schools and terrorist attacks
are starting to blur. B¨
ockler, Leuschner, Roth, Zick, and Scheithauer (2018) recently presented a set of hypotheses about similarities between
the developmental pathways of school attackers and lone actor terrorists. To date there is only a small body of empirical research comparing
these two forms of targeted violence in depth. In order to fill this gap, this article presents findings from a qualitative analysis of prosecution
files comparing the developmental pathways of German school attackers (N= 7; age range: 13 to 23) and Jihadi attackers (N= 7; age range:
21 to 28 years) who committed their attacks between 2000 and 2013. Using theoretical coding and constant case comparison, the contribution
shows that the two phenomena have overlaps in which developmental processes and social mechanisms are similar. Both school attackers and
Jihadi attackers frame their act of violence using cultural scripts and perform the attack on a public stage where victims are attacked not on
the basis of personal conflicts but because of their symbolic meaning. Taking into account the similarities in the perpetrators’ developmental
pathways, the authors propose that it might be more fruitful from an operational perspective to discuss severe target school violence and
terrorist attacks under a common concept of demonstrative violence than to artificially assign them to exclusive classes of violence.
Jihadism, terrorism, radicalization, school shooting, developmental pathway, qualitative study
Address for correspondence
Nils B¨
ockler, Institute Psychology and Threat Management,
Postbox 11 07 02, D-64222 Darmstadt, Germany. E-mail:
ISSN 2192-001X/18/$35.00 © 2018 – IOS Press and the authors. All rights reserved
This article is published online with Open Access and distributed under the terms of the Creative Commons Attribution Non-Commercial License (CC BY-NC 4.0). 5
N. B¨ockler et al. / Comparison of School Attackers and Jihadi attackers
Incidents of severe targeted school violence and
terrorist attacks are usually considered as distinct
social phenomena, although no clear and unequivocal
definitions have been formulated for either. Severe
targeted school violence is generally understood as
targeted attacks committed by (former) school stu-
dents, where the school is deliberately selected as the
location and lethal weapons are used with the inten-
tion to kill (e.g. Bond¨
u, Cornell, & Scheithauer, 2011;
u & Scheithauer, 2014a). While these incidents
are driven by personal motives associated with the
school context and usually understood as personal
revenge for experiences of humiliation (for exam-
ple Vossekuil, Fein, Reddy, Borum, & Modzeleski,
2002), terrorist attacks are normally defined as acts
of violence directed against a political or societal
order (Crenshaw, 2001). Terrorism is always embed-
ded within a communication strategy designed to
have far-reaching psychological effects beyond the
immediate victim(s), namely by generating public
fear within a wider audience. The addressees might
be a rival ethnic or religious group, an entire country, a
national government, a political party, or public opin-
ion in general (Hoffman, 2006). Hence, terrorism is
defined as “asymmetrical deployment of threats and
violence against enemies using means that fall out-
side the forms of political struggle routinely operating
within some current regime.” (Tilly, 2004, p. 5).
According to the current state of research
(Newman, Fox, Harding, Mehta, & Roth, 2004), dif-
ferences between severe targeted school violence
and terrorist attacks are found in the locations tar-
geted (schools vs. public places), and above all in the
motives: tending to be personal in the case of rampage
school attackers, political/ideological or religious in
the case of extremist or terrorist violence. Addi-
tionally, the two phenomena are investigated within
different research traditions, exhibiting few points of
contact to date.
However, several incidents that have occurred over
the past ten years in Europe appear to combine ele-
ments of both severe targeted school violence and
terrorism. One example is the case of Pekka A.,
who killed eight people and himself in a school in
Jokela, Finland, on November 7, 2007. A media
portfolio prepared beforehand included the follow-
ing statement: “Attack Type: Mass murder, political
terrorism (although I chose the school as a target,
my motives for the attack are political and much,
much deeper and therefore I don’t want this to be
called a ‘school shooting’)” (Pekka A., in Oksa-
nen, Nurmi, Vuori, & R¨
anen, 2013). Before the
attack, Pekka A. had pursued an intense interest
in right-wing extremist violence (ibid.). Another
relevant case is the Oslo/Utøya attack in 2011,
which was characterized by elements of an extrem-
ist motivated attack. In their study of the writings
of the attacker, Anders B., Sandberg, Oksanen,
Berntzen, and Kiilakoski (2014) demonstrate that the
attacker was not only influenced by the rhetoric of
right-wing Islamophobic groups, but also by the cul-
tural script of school shootings. In advance of the
attack, B. withdrew almost completely and restricted
his social life to the online context. His prepara-
tions for the attacks were comprehensive, drafting
numerous statements justifying his actions and pre-
senting himself as the defender of European culture.
The modus operandi of his attack at the Work-
ers’ Youth League summer camp on the island of
Utøya also showed strong parallels to school shooting
Similarly, in the 2016 attack on the Olympia shop-
ping mall in Munich, Germany, elements typically
discussed in connection with severe targeted school
violence can be identified (shooting attack on young
people by a lone perpetrator, reading of Peter Lang-
man’s Why Kids Kill), as well as features of a
right-wing extremist attack (only migrant victims,
political message: “wipe out Turks”). The classifi-
cation of this attack remains politically contested
in Germany. While politicians and law enforcement
agencies categorize the attack as a rampage shoot-
ing, researchers tend to classify it as a case of lone
wolf terrorism (Hartleb, 2017). In the past ten years
there have also been cases with an Islamist back-
ground combining elements of rampage shootings
and terrorist attacks. Examples of such incidents in
Germany would include the attacks at Frankfurt Air-
port in 2011 (B¨
ockler, Hoffmann, & Zick, 2015),
urzburg (Meloy & Pollard, 2017), and Ansbach in
2016 (Eddy, 2016).
The occurrence of cases including elements from
both phenomena is not surprising, considering the
observable changes in terrorist strategies over the past
twenty years. For example, in the field of right-wing
extremism, American racists Tom Metzger and Alex
Curtis propagated “leaderless resistance” as a white
resistance strategy in the late 1990s (Borum, Fein,
& Vossekuil, 2012; COT, 2007). Similarly, tenden-
cies of individualization of terrorist strategies are also
observable in the field of Jihadist terrorism since al-
Qaeda called on followers to engage in leaderless
or individual jihad (Sageman, 2008). A number of
terrorist attacks in the style of a rampage killing by
6 International Journal of Developmental Science 1-2/2018, 5–24
N. B¨ockler et al. / Comparison of School Attackers and Jihadi attackers
individual perpetrators or small groups later followed
such recommendations.
On the other side, cases like the Jokela school
shooting demonstrate that at least sometimes a young
person committing a targeted attack in a school
intended to send a political message and had an
affinity to terrorism. Malkki (2014), focusing on the
presence of political elements in school shootings,
distinguishes three types: Cases with explicit political
communication by the perpetrator(s) (type 1), cases
in which the perpetrator(s) made references to earlier
attackers (type 2), and isolated cases in which the per-
petrators made no references at all (type 3). In terms
of the motivational structure, type 1 and type 2 appear
most comparable with acts of terrorism. As in the field
of terrorism, perpetrators of targeted school violence
have also influenced a wider audience. Larkin (2009)
demonstrates how the school shooting at Columbine
High on April 20, 1999, in particular, created a cul-
tural script for later school attacks. Columbine High
stood out from other incidents of targeted violence in
schools, in the sense that both perpetrators regarded it
as a subversive act of political violence in the name of
all who experience social repression at school (“rev-
olution of the dispossessed”).
This growing phenomenon of combination of ele-
ments of terrorist attack and targeted school attack
has initiated a discussion concerning the similarities,
with a growing number of comparative studies. Lank-
ford and Hakim (2011) compared American school
shooters with Palestinian suicide bombers and found
strong parallels in terms of psychological constitution
and motivation. The perpetrators in their study share
many characteristics in common, such as a highly
troubled childhood, social deprivation, and low self-
esteem. In both cases, personal crises represent the
starting point for the turn to violence, with the under-
lying motives of avenging injustice and acquiring
fame and repute. The study builds on the observation
that both groups are homicidal-suicidal. Lankford
and Hakim criticize the widespread dichotomy that
regards school shooters as psychologically unstable,
suicide bombers as extremist but rational. Accord-
ing to their findings, the differences between the two
groups are cultural rather than personal in nature.
Similar results are found by McCauley, Moskalenko,
and Van Son (2013) in their comparative analysis of
school shooters and politically motivated attackers:
in both cases the perpetrators planned their actions
in advance, usually acted alone, and drew their moti-
vation more from emotional/social than material or
instrumental needs; biographies in both groups are
characterized by depression, despair, and suicidal
tendencies. Significant differences exist only in rela-
tion to age and marital status: Politically motivated
attackers are considerably older and more likely to be
Capellan (2015) compared ideological and non-
ideological active shooter events in the United States
between 1970 und 2014, finding similarities in
the demographic and personal profiles, but signifi-
cant behavioral differences between non-ideological
and ideological motivated perpetrators. Capellan’s
empirical findings indicate that ideological shoot-
ers act more methodically and show higher levels
of sophisticated planning, have experienced some
kind of military training, and use a greater number
of firearms. But for the most part the shooters in both
groups were white males in their thirties with dys-
functional adult lives, single or divorced, with lower
levels of education and a history of mental illness.
Capellan argues that the reason for these similari-
ties is that – whether ideological or non-ideological –
shooters were driven by both personal frustrations
and aversion towards society, interpreting the two
phenomena as subgroups of a homicide type that he
calls “lone actor grievance fueled-violence.
Liem, Van Buuren, De Roy van Zuijdewijn,
onberger, and Bakker (2018) compared charac-
teristics of lone actor terrorists in Europe in the period
2000–2016 with “ordinary” homicide offenders. The
demographics and perpetrator profiles led this group
of authors to nearly the same conclusions as Capellan,
with the difference that the ideologically motivated
perpetrators exhibited higher levels of education than
the “ordinary” homicide offenders. It is also note-
worthy that ideological lone actors were not usually
socially isolated, and operated in dyads and triads
more often than “ordinary” homicide offenders, who
usually acted alone.
ockler, Roth, Stetten, and Zick (2014) argued
that besides being risky for development, violent
behavior is also – temporarily – highly functional
and productive for the psychosocial wellbeing of the
perpetrator. In order to gain a deeper understand-
ing of the developmental pathways towards school
shootings and terrorist attacks, and to comprehend
individual motivations, we have to move beyond
the mere accumulation of empirical findings. What
is needed is a theoretical point of reference that
provides some guidance for interpretation and facil-
itates the important progression from description to
explanation. B¨
ockler et al. (2014) point out that –
along with the push factors generating pressure to
International Journal of Developmental Science 1-2/2018, 5–24 7
N. B¨ockler et al. / Comparison of School Attackers and Jihadi attackers
cope with intrapersonal tensions – it is important
to look at the pull factors and relational dynamics
that make a specific action attractive. From a social
psychological point of view, we must therefore also
consider (radicalizing) contexts in which narratives
and scripts supporting violence are disseminated, and
the question of how these contexts are adopted by the
perpetrators. This perspective is also reflected in sev-
eral works focusing on the question of how lonely a
lone wolf really is. Borum et al., (2012) note that cases
in which the perpetrator plans an attack completely
without outside influence, encouragement or inspira-
tion are very rare. In this context van Buuren (2012)
points out that also most lone actor terrorists under-
stand themselves as part of a broader community,
while virtual spaces, especially social media, often
function as a surrogate for offline social networks.
Demonstrative Targeted Violence: A Sensitive
ockler and colleagues (2018) recently introduced
the concept of demonstrative targeted violence to
describe the overlap between severe targeted school
attacks and terrorist violence. While demonstrative
targeted violence generally occurs in a public space,
the victims are selected for their symbolic signif-
icance to the perpetrator. According to Leuschner
(2013) this kind of violence involves a demonstra-
tion of the vulnerability and destructibility of what
the perpetrator regards as a powerful group or insti-
tution: there is always a communicative meaning that
transcends the attack itself. B¨
ockler and colleagues
(2018) describe such acts of demonstrative targeted
violence as an expression of personality in which
the perpetrators seek to gain social recognition by
presenting their personal and/or social identity on
a public stage. This self-staging in turn indicates a
social identification with scripts of violence, groups,
and/or ideologies. On the other hand, the act of
demonstrative violence is also a form of directed com-
munication seeking to draw attention to injustice, to
spread fear and panic, or to mobilize others to fight
for the same cause. However, it also indicates the
perpetrators’ need to justify their actions to them-
selves and others. Against the background of these
fundamental similarities in the modus operandi of
severe targeted school attacks and terrorist attacks,
ockler and colleagues (2018) present a theoreti-
cally grounded pathway model for the development
of demonstrative targeted violence.
While perpetrators of targeted violence in schools
and terrorists generally seem to exhibit functional
cognitive processing of reality, personal grievances
and crises mark the start of a developmental process
leading to an act of demonstrative violence. In this
context, the planned style of targeted school attacks
and terrorist attacks also suggests similarities in the
preparation processes, the planning phase, and the
acquisition of competence at violence. The existing
research on both school shootings and terrorism indi-
cates that the perpetrator’s redefinition of self from
victim to self-perceived avenger is associated with
self-empowerment for violent action. The perpetrator
increasingly moves into a phase of clandestine plan-
ning characterized by a state of tension between secret
private rituals and public intimation (leakage) (Gill,
2015; Meloy & O’Toole, 2011; Meloy, Mohandie,
Knoll, & Hoffmann, 2015). Many investigators have
been able to reconstruct different trigger events after
which the perpetrator might view the act of violence
as necessary, justified, inevitable, and meaningful
(Corner & Gill, 2015; Heitmeyer, B¨
ockler, & Seeger
2013; Meloy & Gill, 2016).
The presented heuristic model (Fig. 1) forms
the backbone for our theoretical coding proce-
dure and the constant case comparison. Our aim
is not to test the above mentioned model in
a hypothetico-deductive manner, but to treat it
as a sensitive concept from which we derive
an empirically grounded model of perpetrators’
developmental pathways towards demonstrative vio-
lence. To use Blumer’s words: “Whereas definitive
concepts provide prescriptions of what to see, sen-
sitizing concepts merely suggest directions along
which to look ( . . . ) they rest on a general sense
of what is relevant” (1954, p. 7). We therefore
constantly consolidate, modify, and differentiate
categories using case comparison and combine
these findings with the hypotheses arising from
the theoretical knowledge in the field (Kelle, 2007).
Our study is based on data collected within the
national research project “TARGET – Case analy-
ses of severe targeted violence” which set out to
analyze all incidents of severe targeted violence in
Germany between 1999 and 2013. For case recruit-
ment (see Fig. 2 ) we distinguished two groups: severe
8 International Journal of Developmental Science 1-2/2018, 5–24
N. B¨ockler et al. / Comparison of School Attackers and Jihadi attackers
Figure 1. Heuristic model - Developmental pathway of school
attackers and terrorist attackers.
targeted school violence comprising attempted or
completed attacks in schools, 1. committed by a
current or former student of the school, 2. planned
and executed with potentially lethal weapons and the
intention to kill one or more persons associated with
the school, 3. where the attack at least commenced,
and 4. when the perpetrator had not yet reached the
age of twenty-five; and targeted attacks with ideolog-
ical or religious background comprising attempted or
completed attacks directed against the political order
in which perpetrators referred to an ideological or
religious worldview.
For case identification we conducted systematic
recruitment by keyword search with German search
terms “Terroranschlag(terrorist attack),“Amok
Figure 2. Sampling process.
(rampage), and “School shooting(school shoot-
ing) in media reports, using the electronic media
archives Genios and LexisNexis which cover about
340 German-language newspapers and journals. We
identified forty-six targeted attacks in schools and
forty-seven targeted attacks with ideological or
religious background. In a second step, identified
cases were categorized by two separate researchers
using the identified media materials and our afore-
mentioned definitions. For deeper investigation we
selected thirty-five cases of targeted attack in schools
and twenty-one cases of targeted attack with ideo-
logical or religious background. In all selected cases,
we requested access to the prosecution files. After
initial analysis of the documents, we excluded all
cases which did not fulfill our criteria (see above).
After this third step, we were left with a sample of
nineteen (attempted or realized) targeted attacks in
schools and twenty-one targeted attacks with ideo-
logical background.
For the case analyses and comparisons in the
present contribution we used a subsample of symbolic
school attacks and homicidal attacks with jihadi ter-
rorist background. Cases of severe targeted school
attack were classified as attempted or completed
International Journal of Developmental Science 1-2/2018, 5–24 9
N. B¨ockler et al. / Comparison of School Attackers and Jihadi attackers
symbolic school attack if victims were chosen
for their symbolic meaning as members of the
school rather than because of personal conflict.
Homicidal attacks with jihadi terrorist background
were defined as attempted or completed attacks
in which the perpetrator(s) referred to a jihadi
movement or organization. We included only per-
petrator(s) who had been socialized in Germany
before they decided to plan an attack, and excluded
cases where the perpetrator(s) entered Germany
specifically to commit an act of terrorist violence.
Ultimately, seven cases of (attempted) symbolic
school attack by single perpetrators were selected
(seven perpetrators)(see Table 1), and three cases
of (attempted) homicidal attack with jihadi ter-
rorist background (with seven perpetrators)(see
Table 2). All incidents investigated occurred in
The school attackers’ ages ranged from 13 to
23 years (M = 17.72, SD =2.8); two offenders were
female and four committed suicide after the offense.
The terrorists’ ages ranged from 20 to 28 years
(M = 23.00, SD = 2.9); all were male, none committed
suicide in connection with the incident.
Materials and Data Analysis
Data about attacks and perpetrators includes prose-
cution files and additional material such as interviews
with imprisoned perpetrators. All files included
witness statements and police reports. For ten perpe-
trators the files include court judgements and forensic
psychological assessments, and for eleven perpe-
trators personal writings and testimonies. We first
ordered all relevant information about the perpe-
trators chronologically from birth to offense, and
prepared biographical case descriptions in order to
analyze the developmental trajectories of perpetra-
tors. In the next step, data was coded following
the theoretical coding method (Strauss & Corbin,
1990). Two researchers coded the material indepen-
dently and discussed diverging interpretations until
agreement was reached. In this way, biographical
trajectories, relevant life events, and turning points
were reconstructed for each case, and developmen-
tal pathway types were described. For the present
paper important concepts and categories gained from
inductive analysis were used for an in-depth case
comparison of the subsample of cases from both case
According to our theoretical concept (B¨
ockler et al.,
2018) we will describe similarities and differences
between the two groups of perpetrators in terms of
their developmental pathways in the run-up to the
violent attacks.
Dispositions and Functional Processing of
In our analysis there is little evidence for the
hypothesis that pathways towards targeted attacks in
schools or jihadi terroristic attacks are determined by
mental disorders. Only in one case of school attack
(7 SA) there is evidence for a lack or loss of ability
to exercise control in the attack situation caused by
schizophrenia. In the sample of terrorist attackers we
found no evidence at all of a causal effect of men-
tal disorders. Nevertheless, there is evidence in all
cases that mental disorders and specific mental dispo-
sitions may have framed the perpetrators’ perception
of reality and social relationships. Mental disposi-
tions are understood here as the result of individual’s
personality and early socialization experiences. Our
case analyses revealed two typical dispositions from
early childhood on: aggressive and impulsive ten-
dencies on the one hand, and introverted characters
on the other hand. Within the first type, subjects
showed aggressive and impulsive tendencies and low
self-control as a result of early problems in the fam-
ily setting (disrespect, domestic violence, or sexual
abuse). These individuals also showed early behav-
ioral problems in the peer context and school, often
classified as antisocial behavior, attention deficit, and
hyperkinetic disorder. While none of the investigated
school attackers fell into this category, the sample
of jihadi terrorist attackers included four cases in
which the subject for example attracted attention
with criminal and dissocial behavior in the run up
to their radicalization. The second class of perpe-
trators presents as sensitive, introverted, inwardly
focused, and non-assertive in advance of the attack.
Some of them had health issues and physical abnor-
malities (which might have been the cause for low
self-esteem), poor social skills, and poor school per-
formance. One school attacker (6 SA) suffered from
Klinefelter’s syndrome, which can cause symptoms
like small testes, tall stature, gynecomastia, and fail-
ure of normal sperm production (Nahata, Rosoklija,
Yo, & Cohen, 2013). He was teased continuously
10 International Journal of Developmental Science 1-2/2018, 5–24
N. B¨ockler et al. / Comparison of School Attackers and Jihadi attackers
by his peers about these physical symptoms, which
resulted in low self-esteem and depressive with-
drawal. Within their further developmental pathways
some of the later perpetrators evolved a compen-
satory narcissistic or schizoid personality structure.
Among the sample of school attackers, all seven cases
show some indications of personality anomalies, but
there were no proper psychiatric or psychological
diagnoses. In the sample of terrorist attackers two
individuals showed clear internalized coping behav-
iors, along with narcissistic personality accentuations
in advance of the attack. The cases 2 TER and 7 TER
repeatedly experienced depressive and partly suici-
dal tendencies. In social contexts they presented as
reserved and showed very little personal initiative.
While withdrawing from society and everyday social
life they developed compensatory fantasies of being
omnipotent avengers and taking part in violent
For all school attackers and jihadi terrorists in the
sample we can identify grievances in socialization
contexts (family, peer group, and school), which in
some cases culminated in personal crises subjectively
perceived as highly significant. In most cases these
experiences were associated with major life changes
that triggered severe feelings of powerlessness and
The Family Context: Problematic Parenting Styles
and Lack of Social Support
There is considerable variation in the formal com-
position of the families in which the perpetrators
grew up –ranging from intact nuclear families,
single-parent families, to foster families. In all
of these socialization contexts problematic social
dynamics were identifiable. In the sample of school
attackers most parents experienced their child as
physically weak and clumsy in interpersonal rela-
tionships but in none of these cases did parents
actively support the process of identity exploration.
Instead they pressured their children toward their
own preferred outcomes, such as academic per-
formance, sporting success or masculinity. Thus,
personal crisis often resulted from discrepancies
between parental expectations and self-awareness.
One typical example is a case where the parents
always compared the young man with his successful
older brother (1 SA). They pressured him to attend
a selective academic secondary school. His fail-
ure there was the initial trigger event for the later
In the cases of jihadi terrorists, the subjects felt
somehow insecure and disoriented in their families.
For both groups, the dominant factor seems to be
a familial atmosphere characterized by emotional
indifference and a lack of parental involvement. The
parents of the later perpetrators were mainly con-
cerned with their own worries and activities, and
showed little presence in the life of their children. In
some cases family life was overshadowed by burden-
some social dynamics derived from parental divorce
and associated perceived crises of loyalties (3 TER, 6
TER). Illness and death of significant others (7 TER,
5 TER) and long-term separation (1 TER, 2 TER)
were also identifiable factors. 1 TER and 2 TER for
example felt totally separated from their family and
their familiar culture, before they jointly decided to
plant bombs in two German passenger trains. 1 TER
and 2 TER came to Germany to study, two years
before the incident. Soon they felt overwhelmed by
multiple stressors, with spatial separation from their
families creating pressure to perform and exposing
them to new unknown cultural codes. While 1 TER
quickly tried to compensate his feelings of disori-
entation by escapism in Salafist ideology, 2 TER
spent most of his time aimlessly surfing the internet,
before 1 TER eventually recruited him for his attack
Our case analyses reveal that perpetrators with
migration background (1 TER, 2 TER, 4 TER, 5
TER) often perceived themselves as experiencing a
challenging balancing act between two cultures. They
perceived Western culture and behavioral codes they
were confronted with in school and at work as a world
apart from their family life at home. Their parents
were not well integrated and – due to lack of language
skills – communication between parents and schools
was often difficult. Within their Western living con-
texts, the young people deeply missed functioning
role models, as they found themselves forced to face
the challenges of everyday life on their own. A futile
search for orientation became a central element in
the developmental pathways of 4 TER, 5 TER and 7
5 TER, for example, stated during the police inves-
tigation he started to perceive his father as a weak man
after he moved to Germany. He was obviously unable
to cope with life in German society. 5 TER soon was
yearning for other role models, whom he eventually
International Journal of Developmental Science 1-2/2018, 5–24 11
N. B¨ockler et al. / Comparison of School Attackers and Jihadi attackers
found in the authoritarian but charismatic preach-
ers of a local Salafist group. 7 TER also described
his father’s severe illness as a turning point in his
life. After a heart attack, his father was unable to
work and became increasingly dissatisfied with his
situation. During this time, 7 TER started to regard
himself as a good-for-nothing: He was unable to con-
tribute any income to the family and, at the same time,
failing at school. When he eventually had to repeat
a grade, he perceived himself as a complete disap-
pointment for his parents. Due to a great sense of
shame, he failed to tell them when he had to repeat
a second year, and eventually left school without any
The Peer-context: Disrespect and Bullying among
The peer context can be understood as the most
important social space in the phase of identity for-
mation. For the school attacker sample, it is obvious
that this social space is experienced as problem-
atic and exclusionary from the perspective of the
later perpetrator. Nearly all of the later perpetra-
tors felt harassed, persecuted, threatened, or hurt
by the majority of their peers. Early experiences
of exclusion by peers fuel a process of social
withdrawal and create a strong need for public
recognition. Several cases illustrate how early expe-
riences of peer exclusion created a continuous point
of reference for violent thoughts: One perpetrator
wrote in his diary five months before the attack
that he had never forgotten the feelings of shame
and helplessness when he was beaten on a school
excursion six years previously (5 SA). Another per-
petrator reported on a psychological counselling
website that his experience of public humiliation
by his peers was the turning point that gener-
ated a strong desire for revenge (2 SA). While all
investigated school attacker cases feature at least
subjective peer exclusion, such experiences of humil-
iation were not identified in the sample of terrorist
The School and Workplace Context: School and
Work Problems
For both groups, school attackers and jihadi terror-
ists, formal educational careers were characterized
by inadequate performance in school and univer-
sity, dropout and precarious employment. In these
contexts, we identified two central patterns: In the
first pattern the perpetrators initially showed no
abnormalities in their conduct at school or work.
A drop in performance, or withdrawal from peers
and colleagues, marked significant changes in their
behavior. In two cases in the jihadi terrorist sam-
ple (3 TER and 1 TER), classmates reported that
the later perpetrators attracted the attention of
teachers and peers when they suddenly started to
glorify terrorist organizations and violence. Quit-
ting school and work were active decisions by
the later perpetrators, triggered by personal crises,
a successive orientation towards ideological con-
texts, and the prioritization of religious practices.
For those who quit school early, this pathway con-
tinued with precarious employment and uncertain
In the second pattern, later perpetrators had dif-
ficulties coping with school from the start and had
to repeat several grades. Some school attackers and
some of the Jihadi attackers also experienced heavy
parental pressure to perform. In both groups we
observed conflicts between the later perpetrators and
teachers as well as classmates. In one case of severe
targeted school violence, the perpetrator attacked a
teacher who he felt had humiliated him seven years
previously (6 SA). Another perpetrator who was
expelled from school for falsifying a medical certifi-
cate only targeted teachers in his shooting attack (1
While later school attackers showed a cognitive
fixation on previous humiliations by peers and teach-
ers, we were not able to identify the same for the
terrorist attackers, whose orientation on ideologi-
cal contexts played a compensatory, structuring and
sense-attributing role. In the course of their radical-
ization process, ideologies, faith-based practices and
group dynamics increasingly replaced other every-
day activities. Positive social feedback, which the
later perpetrators perceived as important for the sta-
bilization of their identity, increasingly came from
ideological contexts.
The personal grievances the perpetrators of both
groups suffered in the course of their biographies
present as very diverse. The common factor is per-
ceived fundamental incongruences between real-self
and ideal-self, resulting in severe chronic strains
and extreme strategies to cope with them. These
grievances produced an “openness” for ideological
contexts and alternative worldviews, as constrain-
ing ties bonding them to socialization agents outside
of radical contexts were absent (Snow, Zurcher, &
Ekland-Olson, 1980).
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Identification with Ideological and Cultural
Scripts and Redefinition of Self-Concepts
Exposure to and confrontation with general
mythodologies of violence eventually set the course
towards the violent acts. Sutterl¨
uty (2004) describes
such mythodologies as scripts in which the use of
violence is linked to categories like power, strength,
and manhood – for example as presented in many
films, computer games, and other cultural products
(Kellner, 2013). We identified a strong fascination for
such narratives in almost all the investigated school
attacks. This was, for example, reflected in intensive
reception of action and horror movies, computer
games, and in strong identification with warriors,
fighters and, in some cases, even mass murderers.
uty (2004) points out that perpetrators who
refer to such mythodologies of violence often asso-
ciate their planned deeds with great expectations –
namely to gain social recognition by exerting power
over others. At the same time, these expectations
push them further and further towards the realiza-
tion of their phantasies. This is true for both groups
in our sample – school attackers and jihadi terror-
ists – with the difference that social relationships
and group dynamics played a more central role in
the sample of jihadi terrorist attackers. While friend-
ships and social networks preceded the perpetrators’
adoption of jihadi ideology and (in most cases) also
their readiness to use violence, later school attack-
ers were directly and more intrinsically motivated to
use violence as revenge against those who they felt
had humiliated them. If at all, not offline relation-
ships but online social networks and identification
with former perpetrators conditioned their adoption
of cultural school shooting scripts. However, we were
able to identify forms of ideology appropriation for
school attackers as well as for jihadi terrorists.
Jihadist Attacks: Radicalization Online, in
Friendship Networks, and in Isolated Dyads
For the Jihadi group attackers (1 TER, 2 TER, 3 TER,
4 TER, 5 TER, 6 TER), as well as for the single lone
jihadi terrorist (7 TER) in the sample, growing com-
mitment to ideology and the social collective behind
it drove the radicalization processes further and fur-
ther towards violence. The later perpetrators’ active
engagement with the ideology was initially rooted
in its attractiveness as a rigid and guiding world
view and their desire to belong to a social network
subjectively perceived as morally superior. The jihadi
terrorists in our sample increasingly interpreted their
own life in the light of ideological meaning schemes.
For example, 7 TER’s turn towards Islam evolved
in a period of inner disorientation and depressive
mood. Like 3 TER, 4 TER, 5 TER and 6 TER, 7
TER expected to gain inner peace, structure and dis-
cipline by devoting himself to religious beliefs and
practices. As he had nearly no relationships with
other practicing Muslims, 7 TER tried to learn about
Islam in a rather autodidactic manner – especially via
online social networks. He read the Quran in German
but soon recognized he had reached the limits of his
ability to comprehend. This changed when he came
across Salafist preachers on YouTube who gave him
an easy understanding of the religion by reducing its
complexity to a binary black and white logic. The
algorithms of Facebook and YouTube provided him
with more and more neo-Salafist and jihadist content,
as well as links to forums like the al-Qaeda Global
Islamic Media Front. Over time, 7 TER became
increasingly confident in his ideological knowledge
and at the end of each day, he was satisfied if he had
managed to comply with the strict religious rules and
practices. This represented a possibility to prove him-
self – and by doing so to regain a sense of self-respect.
After his attack, investigators found more than one
thousand jihadist files on 7 TER’s computer – a major-
ity of them propagating the duty of every Muslim to
fight against Western crusaders and unbelievers.
The Role of Social Networks
While most of 7 TER’s radicalization took place in
the context of online social networks, pre-existing
friendship and kinship ties brought 3 TER, 4 TER, 5
TER and 6 TER into contact with radical and ideo-
logical milieus. For example, about five years before
his attack, 3 TER was led to a radical form of Islam
by an acquaintance with whom he had played bas-
ketball. In 3 TER’s words, he had realized that all
the pressing questions about life which had haunted
him since he was thirteen years old found an answer
in Islam. During a period when he felt uprooted, he
decided to convert. From this point on, he spent more
and more time in groups that propagated a radical
interpretation of Islam and sympathized with violent
jihad. 6 TER – in contrast – was socialized in a largely
Turkish circle of friends. The parents of one of his
best friends held extremist beliefs. They repeatedly
invited 6 TER for lunch and dinner. Eventually he
converted when he was sixteen years old. He stated
that conversion to Islam was a rational decision for
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N. B¨ockler et al. / Comparison of School Attackers and Jihadi attackers
him, because Islam provided him with more answers
than any other religion. It was a decision he made dur-
ing a time when he was experiencing problems in the
family and had several severe conflicts with teachers.
3 TER and 6 TER both quickly found strong con-
nections in the Salafist community where they were
entrusted with tasks and functions. 6 TER became an
editor of an Islamist publication that glorified violent
jihad and the mujahedeen’s fight against the West. In
our sample we also identified radicalization processes
in close dyadic friendships, as in the cases of 1 TER
and 2 TER. Malthaner and Lindekilde (2017) demon-
strate the centrality of the building of social bonds
that promote intense loyalty, emotional support, and
intensive interactions for the radicalization of individ-
uals within small groups and dyads. These new bonds
promote increasing isolation from the previous social
environment and draw radicalizing individuals closer
to radical interpretations.
School Attackers and their Perceived
Connectedness: Identification with Other Attackers
While in the sample of Jihadi attackers deep identifi-
cation with other attackers developed in later stages
of radicalization, identification with former attackers
and their self-presentation was an initial starting point
for most of the school attackers’ pathways towards
violence. In drawing on the school shooting script,
they changed their interpretative patterns in relation
to self and world in a manner similar to the terrorist
adopting jihadi ideology. The more they were able to
recognize their own experiences in the biographies
and self-presentation of former school attackers, the
more they considered an attack of their own as an
option, a potential solution to their individual prob-
lems. Our case studies include personal documents,
diary entries and downloaded materials indicating
strong identification with former school attackers: In
one case a female perpetrator wrote the following in
a friendship book at the age of thirteen:
About me: I hate my life! My major role mod-
els: Dylan Klebold & Eric Harris also known
as the rampage shooters of Littleton (ReB and
VoDKa). I don’t go jogging, I’m running amok. I
don’t write poems, I write my suicide note. I don’t
like shopping for clothes, I like to buy weapons.
(translated by authors, case 4 SA)
Another perpetrator wrote in his diary:
ERIC HARRIS – Probably the most reasonable
boy a high school can offer. ERIC HARRIS is god.
There is no doubt. It is terrifying how alike Eric
is to me. Sometimes it feels like I am living his life
again, as if everything is repeating itself. I am not
a copy of REB, VoDKa, Steini, Gill, Kinkel, Weise
or anybody else! I am the advancement of REB! I
learnt from his mistakes, the bombs. I learnt from
his whole life.
(Perpetrator’s diary; translated by authors, case 2
The same perpetrator often visited the website:, and wrote in his diary that he
had read there about the “TCMSD” (Trench Coat
Mafia Section Germany), an online fan base of
school shooting fans. The diary entry ends with the
words: “Outsiders of Germany, unite!” In several
cases perpetrators understood themselves as part of an
online community of individual outsiders. The school
attackers in our German sample who referred to for-
mer attacks and perpetrators also started to produce
self-presentations (photos, videos, writings) like their
role models did in the run-up to their own acts of
violence. These productions reflected their desire to
create a new definition of self, namely a transforma-
tion from victim to morally superior avenger. From
a social relational point of view, the radicalization
processes of school attackers can best be compared
to the radicalization process of the single jihadi lone
operator in our sample who radicalized online in the
context of a virtual community.
Redefinition of Self
In all cases we found one common feature of the
radicalization process, which we describe as a redef-
inition of self-concept (B¨
ockler et al., 2018). During
the process of growing identification with an ideolog-
ical or a violence-glorifying worldview radicalizing
individuals are increasingly motivated to interpret
and consolidate their self-concepts in terms of these
mythodologies. The process comprises not only
growing interest in an alternative radical worldview,
but also its habitualization. We identified different
forms of such processes: sometimes the redefini-
tion of self is overtly presented and verbalized, in
other cases the process proceeded silently and found
expression only in behavioral changes. By comparing
these redefinition processes we were able to identify
typical patterns, which we describe in the following.
14 International Journal of Developmental Science 1-2/2018, 5–24
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From Disrespect and Failure to Recognition and
The first redefinition pattern is focused on public
recognition and individual significance and is found
in all cases of school attackers. Two slightly differ-
ent versions can be described: Firstly, in a resistance
pattern subjects suffered from experiences of disre-
spect and a loss of recognition in social relationships,
in the family or, more often, in the peer context (2
SA, 4 SA, 5 SA, 6 SA, 7 SA). They regarded them-
selves as at the mercy of others and felt discriminated
and isolated. In this pattern we find a strong desire
for revenge for previous slights and social exclusion.
Identification with radical opinions and ideology, and
with associated role models serves to acquire at least
some kind of negative recognition and notoriety. Here
we often found a specific date, on which the later
perpetrator presented their new self-concept in pub-
lic in order to capture the interest and attention of
the exclusionary reference group. In the second ver-
sion of this redefinition pattern, feelings of inferiority
and a strong discrepancy between ideal self and real
capacities are the starting points (1 SA, 3 SA). Typical
features include strong parental pressure regarding
academic performance or masculinity and assimila-
tion in the ideal self of the later perpetrator. When
the subjects realized that they were not able to fulfil
the desires generated by their ideal self, they became
depressed and suffered self-doubt and fear of fail-
ure. From the sample of jihadi attackers, the case
of 7 TER is prototypical here. As his father’s ill-
ness, his failure in school and his family’s financial
difficulties led to extreme feelings of guilt towards
his parents, his desire to stabilize his self-worth, to
feel useful and needed increased more and more. His
orientation towards Islamist content via the internet
satisfied his need for clarity and guided him towards
new social contexts. In the course of his radicaliza-
tion his focus shifted more and more from his own
personal grievances to the grievances of all Muslims.
While he was helpless in the face of his own problems,
ideological contexts provided him with possibilities
to perform a great service in the fight for the global
Muslim community and thereby to identify himself
with the mighty mujahedeen and its martyrs. That pat-
tern is also typical for school attackers, who seek to
communicate a message through a symbolic attack.
However, for school attackers the interest in radical
ideology and violence-related scripts is not content-
related but emotional – a search for significance and
greatness using radical violent means to prove their
prowess and demonstrate their abilities. Both ver-
sion of this redefinition pattern include a shift from
self-perception as failure to self-perception as a sig-
nificant and powerful individual, and a desire for
public recognition.
From Nobody to Charismatic Leader
Some of the later perpetrators were deeply con-
cerned about their social impact (2 TER, 5 TER,
6 TER). From early on, they showed a strong
desire to prove themselves within social networks;
exerting control and influence were central social
motives. They were eager to become opinion leaders
within most of their social contexts. Their demonstra-
tive identification with extremist beliefs (including
intolerance and aggression against non-Muslims, glo-
rification of terrorists) became an important means of
self-expression. These perpetrators served as an iden-
tification figure for other members of the terrorist
group, as they were perceived as determined, self-
confident and extremely dominant in social contexts.
They therefore had an active influence on the radi-
calization processes of others, as they set the trend
for the violent behavior of the group. At the same
time positive social feedback within and from the
radical contexts consolidated the radicalization pro-
cesses of these individuals. For them, radical social
spaces advanced to a main source of their emotional
and social recognition.
From Loneliness to Social Embeddedness
The commitment of these perpetrators (1 TER, 4
TER) to the extremist contexts arose mainly from
social relationships and less from a deep faith in ide-
ology. The central motive for engaging in violent
acts was the desire to experience a stronger sense
of social belonging. Thus, ideology itself played a
subordinate role for this socially dependent type of
perpetrator. Perpetrators in this group were searching
for other individuals to provide them with orientation
and behavioral security. Therefore, they were highly
sensitive to the influence of others. The planning of an
attack also stemmed more from a sense of increasing
commitment towards other people or social networks
than from intrinsic ideological beliefs. Each perpetra-
tor in this category had a close relationship to a person
who he regarded as an authority figure. As these indi-
viduals cut themselves off from networks outside the
radical contexts, they became more and more depen-
dent on their mentors. The radicalization process con-
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N. B¨ockler et al. / Comparison of School Attackers and Jihadi attackers
solidated as a result of their social experiences within
the radical contexts, indoctrination and an increasing
feeling of commitment towards their confidants.
Clandestine Planning
For both Jihadi attackers and school attackers, a phase
of clandestine planning has been identified in the
developmental pathway in the run-up to the attack.
This phase is characterized by self-empowerment
for violent action, increasing thoughts and fan-
tasies about an attack, and clandestine planning (for
example acquisition and handling of weapons, con-
struction of bombs) as well as preparation activities
(for example reconnaissance of targets). The dura-
tion of this phase ranges from two to six months. Our
analyses indicate that clandestine planning is a central
factor in the genesis of symbolic attacks.
Radicalization in social isolation or within small
radical groups is characterized by secrecy, which
produces a restriction of everyday interaction and
communication. Social relationships beyond the rad-
ical social space become weaker and less important.
This means that delinquent thoughts and actions of
the isolated person or radical group have to remain
hidden and protected from discovery by others, espe-
cially law enforcement. The fact of secrecy produces
decisive aspects affecting escalation: Because the
interaction processes with the real or imaginary peer
group are hidden and clandestine, they are subject to a
disinhibition mechanism that causes steadily growing
polarization towards groups and individuals per-
ceived as hostile and confirmation of the perpetrator’s
own convictions. This disinhibition mechanism has
been described both for face-to-face interactions in
clandestine groups and in the context of “online disin-
hibition” (Suler, 2004) for interactions on the internet.
The permanent danger that high risk activities
(attack fantasies, planning, acquisition of weapons,
training) may be discovered, requires clandestine
social structures in the form of hierarchies and
rituals (Mackert, 2011) and associated sanctioning.
It leads to the emergence of protective mechanisms:
In clandestine groups hierarchies serve to exercise
strong control and pressure to conform, in order
to exclude actions that could create danger for
the entire group (such as betrayal). Rituals, such
as collectively committed illegal acts, function
as additional protective mechanisms. Functional
equivalents to these group processes are observed in
connection with both targeted attacks in schools and
Jihadi attacks and can be described as private rituals
and self-controlling behavior.
Clandestine Planning in Small Groups
Within small groups the group hierarchy and dynamic
facilitates the escalation process towards violent
attack. In the case of 3 TER, 4 TER, 5 TER and 6
TER, preparation activities eventually oust more or
less all everyday life activities of the members several
months before the arrest. During their training in a ter-
ror camp run by jihadist militants in Pakistan, 3 TER,
4 TER, 5 TER and 6 TER were ordered to execute
an attack on German territory. After their return from
the Middle East the group procured seven hundred
kilograms of chemicals and stored them in a garage
rented for that purpose. They also moved to a holiday
rental hundreds of kilometers from their respective
places of residence in order to finish their bomb-
making. With only a few exceptions, the perpetrators’
immediate social environment was not privy to their
plans. Wiretap transcripts show that the group had
quite ambivalent attitudes towards their mission. At
first, they were against attacking civilians in Germany
and they desired to fight and die for their brothers
and sisters at the front, rather than kill innocents
in their home country. But the group managed to
overcome these doubts by reinforcing and control-
ling each other. For example, they imagined how the
interior minister would appear on camera after their
attack and talk about the most devastating terrorist
plot since 9/11. Referring to the popular music cast-
ing show, 5 TER stated during the preparations that
he felt like he was on “Terrorist Idol” and that he
was expecting to receive the death penalty at least
deportation to Guantanamo. Collins (2014) describes
such dynamics during the perpetrators’ preparation as
“clandestine excitement.” We also identified similar
processes of isolation and clandestine excitement in
the cases of 1 TER and 2 TER. As the dominant part of
the terrorist dyad, 1 TER was eager to isolate 2 TER
from his fellow students while accelerating his radi-
calization. While preparing their suitcase bombs they
withdrew completely from their social environment.
Like 3 TER, 4 TER, 5 TER, and 6 TER, they had
an exact idea what would happen after their attack.
Their bombs were to explode on the ground while
they were sitting in a plane flying towards the Middle
East. They adjusted the detonators of the explosive
devices according to these plans. With their attack
they wanted to recommend themselves to terrorist
organizations as recruits.
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Clandestine Planning by Isolated Individuals
Similarly, to clandestine planning in small groups
and dyads, isolated actors also build a clandestine
space where their fantasies experience confirmation
and recognition, upon which further cognitive esca-
lation and self-commitment play out, and where
emotional preparation for the act occurs. For school
attackers Collins (2014) describes a “deep backstage”
where young people create a ritualized hidden arsenal
around which their fantasies and activities revolve.
Their knowledge of the illegality of the arsenal
and their own associated potential to kill creates a
clandestine excitement that ultimately supplies the
emotional energy for carrying through the attack
itself. We found evidence for such hidden arsenals
in several cases: perpetrators procured pistols and
trained secretly; in two cases they built pipe bombs.
In most cases the acquisition of weapons was ille-
gal and the perpetrators created hiding places which
they visited periodically. Ownership and handling
of real weapons can itself have an escalating and
urgency-producing effect where the weapons are
experienced as sensually stimulating. They also sym-
bolize the possibility of turning fantasies of power
and vengeance into reality.
Another typical element of clandestine planning
by isolated individuals is the ritualized writing of
diaries in which they absorb themselves in their
fantasies and planning thoughts. Sometimes fantasies
and writings revolve around public reactions after
the planned attack:
I will be the first to go on a rampage with a
blank cartridge pistol. It will restart a discussion
about our gun laws but its all the same to me.
(Perpetrator’s diary, translated by authors) (diary
entry, case 6 SA)
In five out of seven school attack cases (2 SA,
4 SA, 5 SA, 6 SA, 7 SA) we found such writings,
showing a ritualized identification with and glorifi-
cation of the perpetrators of the Columbine School
Shooting in Littleton in 1999 (Eric Harris and Dylan
Klebold). Former school attackers are the “holy pil-
lars” on the private altars of most of the subjects in our
school attack sample (Leuschner, 2016, p. 325). Fans
and imitators form a “virtual community” in social
networks and discuss the possibilities of violent acts
and the pros and cons of different weapons (B¨
& Seeger, 2013).
Strong self-controlling behavior can also be
observed in cases of isolated individuals, but in forms
that are less consistent and characterized by ambiva-
lence between safeguarding the secret and public
intimation (leakage). Alongside secret planning and
private rituals, the new self-concept is also expressed
outwardly and reflected in visibly altered behavior,
for which the term leakage (also leaking) has become
established (Meloy & O’Toole, 2011; O’Toole, 1999;
cf. Bond¨
u & Scheithauer, 2014b). In our analysis
we found that later school attackers created poems,
drawings, and even theater plays, or showed weapons
they already possessed to others. These communi-
cations and the displayed personal redefinition also
generate enormous pressure to carry through the
attack, because any deviation from the leaked plans
and the new role would be experienced as weakness
and potentially interpretable as confirmation of the
earlier self-definition as victim. One could say that
leakage creates a “self-obligation” to carry through
the attack. Of course leakage (announcements and
hints) must never go as far as to create a danger of
the secret attack plans actually being discovered. For
this reason, we also always observe self-controlling
behaviors in lone actors, such as precautionary
measures, diversionary maneuvers, and deception
strategies that serve to keep others from discover-
ing the deep backstage. As such, leakage describes
the perpetrator’s game of hinting at the secret plans
to others while at the same time warding off those
who come too close to discovering the secret – which
heightens the secret excitement (Leuschner, 2016).
Such leakage can also be identified in connection
with lone actor terrorists. As Hoffmann, Glaz-Ocik,
Roshdi, and Meloy (2015) relate, especially with lone
actor terrorists the desire for self-projection often
overpowers the tactical need for discretion, where
the attack planning is not subject to the discipline of
a group. While 7 TER, for example withdrew more
and more from family, peers, and friends, he started to
glorify martyrdom and violent jihad via the internet.
Furthermore he listened to Islamist nasheed songs
that told him to turn away from all infidels. About one
year before his attack, he declared his hatred against
the West in internet chats and forums where he openly
sympathized with terrorists, and described the United
States as personified evil, and toyed with the idea of
joining the mujahideen in Iraq. Few months before
his attack, he started to delete all his non-Muslim
friends on Facebook and added to his profile quite
a number of strangers whose Facebook page indi-
cated some kind of association with Islam. During
this time he focused more and more on the ideolog-
ical world while other spheres of life receded into
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N. B¨ockler et al. / Comparison of School Attackers and Jihadi attackers
the background – as also reflected in the amount of
jihadist content he downloaded from the web.
Escalating Triggers
Even if the deep backstage self-obligation and
escalation mechanisms described above drive
developments to the point of violent action, there is
no automatism. Whether an attack is actually car-
ried out will depend inter alia on concrete events that
may appear in very different forms both for school
attackers and jihadi terrorists. The first and most
important trigger is events that generate pressure to
act, such as events that suggest a concrete external
danger of discovery of attack planning or internal
pressure resulting from the escalating dynamic in
small groups. In the school attacker sample there
is one case where the perpetrator was apprehensive
about the discovery of his weapon arsenal by law
enforcement (2 SA), two perpetrators feared disclo-
sure of their violent plans by classmates (4 SA, 5 SA).
3 TER, 4 TER, 5 TER, 6 TER attracted the attention
of the police when 4 TER and 6 TER reconnoitered
a possible target for their attack, a US military base.
This led to police observation and house searches.
Although 3 TER, 4 TER, 5 TER and 6 TER knew
about the surveillance efforts, they nevertheless con-
tinued with their attack plans. Besides pressure from
law enforcement, we also identified other influencing
events that escalated the situation for later perpe-
trators, for example termination of employment or
stressing social events.
Secondly, we must consider events in the social
setting that radicalized perpetrators perceive as legit-
imization of their ideological beliefs and attack
planning. These can include events experienced as
a massive attack on the in-group and its ideology,
such as acts of violence, vilification, and abuse from
the out-group. Heitmeyer (2012) argues that such
signal events exhibit strong potential for emotional
and moral outrage and as such are certainly suited
to mobilizing individuals and groups to commit vio-
lence. In the case of school attacks, in four cases
the perpetrator experienced a disparagement (such as
expulsion from school) or social reinforcement (for
example father actively supporting the son’s interest
in guns) that was interpreted as a legitimation for the
attack. While 3 TER, 4 TER, 5 TER and 6 TER inten-
sively discussed the legitimacy of an attack as revenge
for Western intervention in the Middle East, 1 TER
for example convinced 2 TER that the publishing of
Mohammed cartoons in German newspapers was one
of the severest possible insults against the Muslim
community. 1 TER framed an attack as a necessary
retaliation against Western society. Shortly before his
attack 7 TER, the lone operator, viewed two videos
on YouTube. The first showed the lifeless but smiling
faces of martyrs accentuated by a heroric nashid, the
second showed a scene from the movie Redacted in
which US soldiers rape a Muslim teenager. 7 TER,
who was not aware that he was watching a Hollywood
movie, was unable to get this scene out of his head.
He was sure that it was sign from Allah who wanted
7 TER – as a proof of his faith – to protect his sisters
from further abuses. The next day, 7 TER killed two
American soldiers at a German airport.
Especially in the case of school attackers, retrau-
matizing events may reactivate earlier negatively
experienced emotional states or negatively connoted
self-images (for example victimization experiences).
For example, a recent slight or subjectively experi-
enced injustice can reactivate the earlier traumatic
experience of loss of status and trigger the actual
intention to carry out the attack. In the school attacks
sample there are two examples (4 SA, 7 SA) in which
the later perpetrators again experience bullying and
social exclusion, reactivating their earlier experiences
and triggering execution of the attack. Finally, perpe-
trators may experience loss events as triggers. One
example would be the end of an important relation-
ship that previously represented a social connection
outside the clandestine radical arena (6 SA).
All four trigger types help the perpetrator to
view the act of violence as necessary, justified,
inevitable, and meaningful. The decisive concrete
trigger or combination of events in a particular case
can generally only be determined retrospectively.
Attempts to identify generally applicable triggers
for acts of violence are therefore pointless. Instead
it must be assumed that in each individual case the
interaction of individual decisions, positive and neg-
ative feedback processes (such as social reflection,
feelings of empowerment), changed perception of
opportunity costs, and biographical breaks become
crystallization points for dominant action patterns
and paths towards violence.
Demonstrative Acts of Violence
For a complete understanding the situations of
violence have to be described as triads of perpe-
trator, victims, and third parties (the audience, both
18 International Journal of Developmental Science 1-2/2018, 5–24
N. B¨ockler et al. / Comparison of School Attackers and Jihadi attackers
Figure 3. Developmental pathways of school attackers and terrorist attackers.
immediately present and via the media) (Leuschner,
2016). A closer look at the concrete situations of
violence reveals that all perpetrators in both groups
chose their victims for their symbolic significance.
Hence, we describe targeted attacks in schools and
acts of terrorism as demonstrative acts of violence:
“Demonstrative violence seeks to spread terror, to
earn respect, to dispel boredom. It has a genuine
social meaning. [ . .. ] Violence in this context is self-
presentation and self-commendation” (Sofsky, 2002,
p. 34; transl. by authors). With respect to the com-
municative meaning of the acts, two aspects need to
be distinguished: Firstly, the communicative mean-
ing can be described as an expression of personality,
where the perpetrator seeks to present their own per-
sonal and/or social identity, and to generate social
recognition. Some terrorism researchers have argued
that a terrorist attack is a kind of altruistic violence
where an individual becomes a faceless ideological
soldier for a group’s cause. However, jihadists are
eager to offer possibilities for recruits to become both
a soldier for the cause and at the same time famous as
an individual (martyr cults, glorification of perpetra-
tors in online magazines like al-Qaeda’s Inspire or the
Islamic State’s Dabiq and Rumiyah) – at least within
the extremist networks, but often also within soci-
ety through intense media coverage. Secondly, the
acts of violence under consideration here are directed
forms of communication. They are bound up with a
message which the perpetrators want to share: for
example, when the perpetrator refers to ideologies,
draws attention to injustice, seeks to spread fear and
panic, or hopes to mobilize others to do the same.
The success of the act thus depends – from the per-
petrator’s perspective – largely on the responses of
the social environment, so that the perpetrator must
ensure that his/her message is understood (Muschert
& Ragnedda, 2011; Waldmann, 2011). For this rea-
son, perpetrators generally seek to shape the public
interpretation of their actions through “manifestos”,
letters, videos, and personal writings. For our sam-
ple that was especially true of the school attackers (2
SA, 3 SA, 4 SA, 5 SA, 6 SA, 7 SA), while the Jihadi
attackers mainly focused on attacking symbolic pub-
lic targets to spread their message. However, at the
same time most of terrorist attackers could rely on
an extremist organization to take responsibility for
the attack. While 3 TER, 4 TER, 5 TER, 6 TER and
International Journal of Developmental Science 1-2/2018, 5–24 19
N. B¨ockler et al. / Comparison of School Attackers and Jihadi attackers
7 TER focused their attack on American soldiers, 1
TER and 2 TER chose to attack civilians in general.
After 1 TER and 2 TER had excluded a famous Ger-
man bridge and a soccer stadium as potential targets
for practical reasons, they decided to focus on pas-
senger trains – inspired by the al-Qaeda attacks in
Madrid and London.
To our knowledge, this is the first study to empiri-
cally analyze the similarities and differences between
school attackers and jihadi terrorists in Germany in
the period of 2000 to 2013 using police files and court
judgements. The sensitive concept proved to be fruit-
ful for the comparative analysis of the developmental
pathways towards targeted demonstrative violence.
While the pathways of the perpetrators in both groups
were quite similar in general terms, the analysis also
brought to light significant variations between the
groups in most of the categories (Fig. 3). Findings
show that the perpetrators’ perception of reality and
developmental pathway may be influenced by men-
tal abnormalities (in both groups) but only in one
case (a targeted school attack) was here any indica-
tion of mental disorder reducing the ability to exercise
control in the attack situation.
All perpetrators in both groups suffered from
grievances in at least one of three socializing con-
texts (family, peers, school/work), accompanied by
fundamental incongruences between their real-self
and ideal-self. In most school attack cases and some
jihadi terrorist cases, grievances culminated in per-
sonal crises that were subjectively perceived as highly
significant and triggered further maladaptive devel-
opment. While the subjective experience of grievance
was identified in all cases, its character differs
between the groups: School attackers mostly suffered
from parental demands and humiliations by peers and
teachers, while jihadi terrorists suffered from a lack of
role models in their family, identity diffusion between
two cultures, and employment problems. These dif-
ferences may also have to do with the fact that the
subjects in the jihadi terrorist sample are on average
about five years older than the investigated perpetra-
tors of targeted violence in schools. In other words,
the two groups are at different developmental stages
(McCormick, Kuo, & Masten, 2011). While the
development of a gender identity, a consistent system
of norms and values, and the establishment and struc-
turing of social friendships are central developmental
tasks in the adolescent phase, the fostering of
economic independence, career development, and
participation in cultural and political life are impor-
tant tasks of (young) adult life.
When we understand radicalization in a broad
sense with Wilner and Duboulos (2011) as “a per-
sonal process in which individuals adopt extreme
political, social, and/or religious ideals and aspira-
tions, and where the attainment of particular goals
justifies the use of indiscriminate violence” (p. 38), it
is noteworthy that individuals in both groups orien-
tate on political-cultural scripts with violent content
which obviously offer a possibility to express them-
selves and to cope with perceived grievances and with
central developmental tasks. In this view perpetrators
who commit symbolic targeted violence in schools
also experience a process of radicalization on their
developmental pathway towards violence. Taking the
personal grievances of both groups into account it
becomes clear that the choice of an Islamist script
on the one hand and a school shooting script on the
other is biographically reasonable in either case. For
the further developmental pathway it is crucial that
the confrontation with a suitable violent script occurs
in the “right moment” when the individual is seeking
a solution for their stressful situation – be it short
term (for example failing in school/work, illness of
a significant other etc.) or long-term stressors (such
as failing to cope with central developmental tasks,
disorientation etc.).
Against this background it is important to note that
radicalization processes never take place in a social
vacuum. This is true for jihadi terrorists as well as
school attackers. While real world social networks
and friendship ties played a central role as radi-
calizing social contexts for Jihadi group terrorists,
virtual social networks and processes of paraso-
cial identification were crucial for school attackers
and the only lone actor terrorist in the sample. The
social negotiation of cultural scripts and constant
feedback within radical social spaces accompanied
the lowering of individual thresholds for use of
violence in both groups. Especially for individu-
als with stronger social anxiety, virtual contexts
offered a possibility to approach a radical group
from a state of social isolation. While close friend-
ships, social involvement, and the attractiveness of
leading a real world group were central motivations
to go further along the path towards violence for
the terrorist subjects, the desire to cope with social
disrespect and failure and to gain (otherwise lack-
ing) social recognition and significance were the
20 International Journal of Developmental Science 1-2/2018, 5–24
N. B¨ockler et al. / Comparison of School Attackers and Jihadi attackers
Table 1
(Attempted) Homicidal Symbolic Attacks in Schools
Case Year Events
1 SA 2002 19-year-old former student shoots dead 12 teachers, two students, one administrative employee, and one police
officer at his former school before shooting himself.
2 SA 2006 18-year-old student injures 36 persons at his former school with firearms and smoke bombs, before committing
3 SA 2009 The shooting of a 17-year-old former student resulted in the deaths of twelve people at his former school and
three civilians, he killed at a car dealership. His flight lasted several hours. He committed suicide, when he was
surrounded by police forces.
4 SA 2009 16-year-old girl plans to stab several teachers and students at her school and set the school on fire using Molotov
cocktails. Detected by a classmate, she injures her and fleees from school. She turns herself over to the police the
same day.
5 SA 2009 18-year-old perpetrator armed with Molotov cocktails and an axe injures fifteen people, two of them severely.
Police quickly arrive on the scene and dt´
etain him.
6 SA 2010 23-year-old former student armed with a knife and a starter pistol stabs a former teacher to death at his former
school. He is arrested shortly thereafter.
7 SA 2011/
Armed with several knives and an axe, a 13-year old girl lights a fire in the school hallway and threatens to kill
classmates. She is arrested without injuring anyone. One and a half year after the first event, after a stay at a
psychiatric clinic, she attacks her classmates at her new school using her father’s gas gun.
*SA = School Attack.
Table 2
(Attempted) Homicidal Attacks with Ideological Islamist Background
Case Year Events
2006 Two perpetrators aged 20 (1 TER) and 21 (2 TER), plant explosive devices in two passenger trains. The attack is
meant to be a retaliation for the publication of Mohammed caricatures in German newspapers. Due to defects the
bombs do not explode and the perpetrators are able escaped to Lebanon. 2 TER is arrested when he returns to
Germany, tried and sentenced to life in prison for attempted murder and attempting to cause an explosion. The
second perpetrator (1 TER) is later arrested in Lebanon.
2007 Four perpetrators aged 22 (3 TER, 4 TER), 27 (5 TER) and 28 (6 TER) are arrested while constructing explosive
devices to attack US targets. Two of the perpetrators are sentenced to 12 (6 TER) and 11 (5 TER) years for
membership of a foreign terrorist organization, conspiracy to mass murder, and coercion. One of the conspirators
(3 TER), who tried to shoot a police officer during his arrest, is also convicted of attempted murder and also
sentenced to 12 years in prison. The fourth perpetrator (4 TER), who was entrusted with acquiring detonators, is
sentenced to five years in prison.
7 TER 2011 21-year-old man with a handgun shoots two US soldiers dead at Frankfurt Airport and severely wounds two
others. Sentenced to life in prison for two cases of murder and three cases of attempted murder in conjunction
with grievous bodily harm.
*TER = Terrorist Attack.
drivers for the school attackers and the lone actor
In both groups the pathways were consolidated
by dynamics of clandestine planning and excitement,
accompanied by the restriction of social interactions
to radical social spaces. While small group dynamics,
mechanisms of group control, and mutual encour-
agement fostered the radicalization processes of the
jihadi terrorist subjects, social withdrawal, private
rituals, and leaking were identified as equivalents for
the lone actor terrorist and school attackers. Espe-
cially the latter mechanisms stimulated fantasies of
omnipotence and a new perception of the self in
distinction to society. While radical spaces become
gradually central for the self-worth of the later
perpetrators, the perception of ongoing grievances,
everyday challenges, moral outrage and in some cases
the stress of law enforcement surveillance served
as escalating triggers and increased the pressure on
subjects to prove themselves according to the new
and redefined violent identity. In the last stage, the
execution of targeted violence serves as an initia-
tion ceremony to join a series of other ideological
motivated avengers and to demonstrate the radical
identity ultimately and irreversibly on a public stage.
From an operational point of view, it makes strong
sense to assess terrorist attacks and targeted violence
in schools using the concept of demonstrative vio-
lence, which allowed us to identify the same core
stages – with different dimensional manifestations –
International Journal of Developmental Science 1-2/2018, 5–24 21
N. B¨ockler et al. / Comparison of School Attackers and Jihadi attackers
in the perpetrators’ developmental pathways for both
phenomena (see Fig. 3 ). That indicates that the two
phenomena are not categorically different. Therefore,
we agree with Borum et al. (2012) that we should
stop devoting resources to scientific definition exer-
cises regarding the number of perpetrators that can
be evolved, the kind of outside support which is
acceptable or the purity of the political respective
ideological motive that is necessary or reasonable
to classify an act of violence as terroristic attack
or a rampage. As hybrid characteristics are rather
the norm than the exception, Borum et al. (2012)
argue that it would be much more effective to view
these factors “along a continuum instead of forcing
unnecessary either-or choices” (p. 393). We pro-
pose the same logic for the developmental stages
defined in the present paper. Future efforts should
focus on identifying and categorizing the character-
istics of warning behaviors at each stage and using
them for the purpose of early detection. But the model
might also be useful for planning effective case man-
agement strategies in the deradicalization and threat
management context, as the localization of a person of
concern in the different stages and sub-dimensions of
our pathway model helps to understand the inherent
logic of a case, the (social) needs the individual links
with his/her behavior, and the social environment
which influences the pathway actively or passively.
Moreover, the model could sensitize a case manager
for potential points of intervention during a process
of escalation.
Limitations and Outlook
Especially in the context of the so-called Islamic
State, terrorism is a very dynamic phenomenon.
We already know that a significant number of the
young people who travelled from Germany to Iraq
and Syria in order to join jihadist militias between
2013 and 2015 were minors. There is anecdotal evi-
dence that social pressure and influence played a
greater role in their decision to fight or to com-
mit attacks in their home country than for the older
perpetrators in our sample, who showed significant
intrinsic motivation. Nevertheless, we also have to
understand the role and pathway of female attack-
ers like Safia S., who tried to kill a policeman at
Hannover central station by stabbing him in the
neck. Radical female jihadi networks and the recruit-
ment of women are also playing an increasingly
important role. However, as most of the criminal
proceedings are still pending, researchers have no
access to the related police files or court judgements
at present. This is also the case for the vast major-
ity of lone operator attacks committed in 2015/2016
when the Islamic State was forced to change its strat-
egy and called on Muslims to stop emigrating to the
Caliphate and to fight the infidels in Western coun-
tries instead. But current developments indicate that
the overlap between terrorist violence and school
attacks is increasing rather than decreasing. With-
out doubt it will be a central task of future research
to test this hypothesis against a reliable database
and it will be a central topic for future development
activities in the domain of preventive interventions
(cf. Cornell & Scheithauer, 2011; Leuschner et al.,
As we have developed the presented empirically
grounded model of “the developmental pathway
towards demonstrative violence” using qualitative
comparative analysis, it is open to change and opti-
mization, on the basis of additional cases analyzed
through the lens of the current work. We should also
ask whether it is possible to categorize other phe-
nomena of targeted violence (for example rampages
committed by adults) under the concept of demon-
strative violence. In the long run, larger reliable data
bases and control groups would be necessary to prop-
erly validate a concept like demonstrative violence.
Author’s Notes
Target Research Project:,
BMBF funding code 13N12646.
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Bio Sketches
Nils B ¨ockler studied educational science and psychol-
ogy. Currently, he is unit manager for extremism and
radicalization at the Institute Psychology and Threat
Management in Darmstadt. From 2010 to 2016 he
was research assistant at the Institute for Interdis-
ciplinary Research on Conflict and Violence (IKG)
at Bielefeld University. His academic work focuses
on patterns of online hate and radicalization. Fur-
ther research interests are school shootings, terrorism
(especially by lone operators), extremism, and social-
VincenzLeuschner is professor of Criminology and
Sociology at the Berlin School of Economics and
Law, Department Police and Security Management.
From 2009 to 2016 he was research assistant at Freie
at Berlin. His research interests are violence
research, sociology of social problems, victimology,
developmental criminology, crime prevention and
security research.
Andreas Zick is director of the Institute for Interdis-
ciplinary Research on Conflict and Violence (IKG) at
Bielefeld University and Professor of Socialization
and Conflict Research at the Faculty of Educa-
tional Science. His research interest concentrates on
prejudice and discrimination, intergroup conflicts,
acculturation, extremism, and violence.
Herbert Scheithauer is Professor for Develop-
mental and Clinical Psychology at Freie Universit¨
Berlin, Germany, and Head of the Unit “Developmen-
tal Science and Applied Developmental Psychology”.
His research interests are bullying, cyberbullying, and
the development and evaluation of preventive inter-
24 International Journal of Developmental Science 1-2/2018, 5–24
... School-related and terrorist attacks share a number of features (Böckler et al., 2018;Bondü et al., 2019), suggesting that these findings may be transferable to terrorist attacks: Both can be considered lowfrequency, but high-impact offenses, often aiming at killing multiple victims with no prior close relationships to the offenders. Offenders are often young males with no consistent offender profile and rather unspecific risk factors. ...
... Akin to school shootings, the focus is on the early detection of individuals who aspire to put extremist beliefs into action (Amman et al., 2017;Buggy, 2016;Capellan & Lewandowski, 2018;Kebbel & Porter, 2012;Meloy & Gill, 2016). Given (a) the strong similarities between school shootings and terrorist attacks (Böckler et al., 2018;Bondü et al., 2019), (b) the now common notion that the form and direction of radicalization largely depends on the accessibility of ideologies (Neumann, 2016), as well as (c) observations of leaking prior to terrorist attacks (Böckler et al., 2015;Böckler, Hoffmann, & Meloy, 2017), previous insights and knowledge about leaking may be utilized for prevention of terrorism as well. ...
... Fourth, most of the studies rely on open-source information. Few studies in the field of risk assessment for the purpose of detecting and preventing terrorist attacks have analyzed police or judicial case files (Böckler et al., 2015(Böckler et al., , 2018Böckler, Hoffmann, & Meloy, 2017). Open-source data collection, though, comes with certain limitations. ...
In the recent past, the numbers of religiously- and politically-motivated terrorist attacks have increased, inevitably raising the question of effective measures to prevent further terrorist attacks. Empirical studies related to school shootings have shown that school shooters reliably (directly and indirectly) disclosed their intentions or plans prior to the attack, a phenomenon termed leaking or leakage. Leaking has been used for preventive purposes in this area of research. Recent research has indicated that leaking was also present prior to politically and religiously motivated terrorist attacks. In order to determine the current state of knowledge about leaking related to these offenses, we conducted a review of the international literature on religiously and politically motivated terrorist attacks. Up to 90% of the offenders showed some type of leaking prior to the attacks. A range of different forms of leaking could be observed. Leaking often occurred in the form of verbal communication with family and friends and/or via communication over the Internet. Terrorist offenders apparently tend to show leaking more often than other groups of mass murderers. Findings regarding similarities and dissimilarities in leaking between religiously motivated, jihadist and politically-motivated, far-right terrorist attacks were contradictory. We discuss the implications of these findings for practice and research as well as the strengths and possible weaknesses of the leaking concept.
... One of them showed that in nearly all cases of school shootings in the United States that happened between 1994 and 2001 radical action was preceded by incidents of peer harassment at school (Leary et al., 2003). Another qualitative study examined adolescent German school attackers and showed that nearly all attackers felt harassed by their peers (Böckler et al., 2018). These studies inform our research only indirectly as they are not focused specifically on political aggression, and it is unclear to what extent their results generalize to a political domain. ...
... Being a victim of peer harassment is a source of insignificance, and it may facilitate interest in radical behaviors as means of mitigating these feelings. These findings are also in line with research showing significant associations between peer harassment and aggressive radicalization (Böckler et al., 2018;Leary et al., 2003;Lyons-Padilla et al., 2015). They extend this research by showing that youth experiences of peer harassment are associated with instantaneous (rather than lagged) changes in their political radicalism and that highly harassed youth have higher radicalism across adolescent years compared to their less-harassed peers. ...
Although political radicalism is one of the major societal threats, we have limited understanding of how it is formed. While there are reasons to expect that harassment experienced in adolescence increase the propensity for radicalism, this relationship has not yet been investigated. This five-wave study of Swedish adolescents ( N = 892) examined the role of peer harassment in radical political behavior. The results revealed that within-person fluctuations in harassment were positively related to fluctuations in radicalism. Individual-level (but not class-level) harassment also predicted differences between adolescents: youth who experienced more harassment had higher levels of and a more pronounced decrease in radicalism. In addition, adolescents who had more supportive teachers or parents were less affected by harassment than youth with less-supportive adults. The findings suggest that personal experiences of harassment increase the risk of radicalism but supportive relationships can mitigate their negative consequences.
... Similarly, a comparison of German school attackers (n = 7) and lone-actor terrorists (n = 7) used qualitative methods to construct developmental pathways to demonstrative violence (Böckler, Leuschner, Zick, & Scheithauer, 2018). Biographical trajectories, life events, and turning points were coded by two researchers and collated to describe differential pathways to attack. ...
... For instance, studies have examined the conceptual boundaries between different lone-actor grievance-fuelled offenders. These include comparisons of suicide terrorists with rampage, workplace, and school shooters (Lankford, 2013), suicide terrorists with mass shooters (Lankford, 2016(Lankford, , 2018Lankford & Hakim, 2011), ideologically and nonideologically motivated mass shooters (Capellan & Anisin, 2018), political and non-political murderers in Northern Ireland (Lyons & Harbinson, 1986), adolescent targeted school attacks with jihadi terrorists in Germany (Böckler et al., 2018), both far-right homicides (Gruenewald, 2011;Gruenewald & Pridemore, 2012), and European lone-actor terrorists with common homicides (Liem et al., 2018), and lone-actor terrorists with mass murderers (Capellan, 2015;Gill et al., 2014;Horgan, Gill et al., 2016). ...
Research on terrorism is increasingly empirical and a number of significant advancements have been made. One such evolution is the emergent understanding of risk factors and indicators for engagement in violent extremism. Beyond contributing to academic knowledge, this has important real-world implications. Notably, the development of terrorism risk assessment tools, as well as behavioural threat assessment in counterterrorism. This thesis makes a unique contribution to the literature in two key ways. First, there is a general consensus that no single, stable profile of a terrorist exists. Relying on profiles of static risk factors to inform judgements of risk and/or threat may therefore be problematic, particularly given the observed multi- and equi-finality. One way forward may be to identify configurations of risk factors and tie these to the theorised causal mechanisms they speak to. Second, there has been little attempt to measure the prevalence of potential risk factors for violent extremism in a general population, i.e. base rates. Establishing general population base rates will help develop more scientifically rigorous putative risk factors, increase transparency in the provision of evidence, minimise potential bias in decision-making, improve risk communication, and allow for risk assessments based on Bayesian principles. This thesis consists of four empirical chapters. First, I inductively disaggregate dynamic person-exposure patterns (PEPs) of risk factors in 125 cases of lone-actor terrorism. Further analysis articulates four configurations of individual-level susceptibilities which interact differentially with situational, and exposure factors. The PEP typology ties patterns of risk factors to theorised causal mechanisms specified by a previously designed Risk Analysis Framework (RAF). This may be more stable grounds for risk assessment however than relying on the presence or absence of single factors. However, with no knowledge of base rates, the relevance of seemingly pertinent risk factors remains unclear. However, how to develop base rates is of equal concern. Hence, second, I develop the Base Rate Survey and compare two survey questioning designs, direct questioning and the Unmatched Count Technique (UCT). Under the conditions described, direct questioning yields the most appropriate estimates. Third, I compare the base rates generated via direct questioning to those observed across a sample of lone-actor terrorists. Lone-actor terrorists demonstrated more propensity, situational, and exposure risk factors, suggesting these offenders may differ from the general population in measurable ways. Finally, moving beyond examining the prevalence rates of single factors, I collect a second sample in order to model the relations among these risk factors as a complex, dynamic system. To do so, the Base Rate Survey: UK is distributed to a representative sample of 1,500 participants from the UK. I introduce psychometric network modelling to terrorism studies which visualises the interactions among risk factors as a complex system via network graphs.
... Across the terrorism literature, qualitative studies have identified numerous preceding factors or vulnerability indicators for involvement in terrorism, such as individual needs, relational patterns, ideological affiliations and narratives, triggering events as well as group identities, just to name a few (e.g., Böckler, Leuschner, V., Zick, A., & Scheithauer, 2018;Lindekilde et al., 2019a). However, these 'risk factors' are neither sufficient to explain radicalisation nor will they be present within every radicalised individual (Borum, 2011;Jensen et al., 2016;Webber & Kruglanski, 2018). ...
Progress within the field of radicalisation is evident. Yet while research increasingly adopts a quantitative approach to studying radicalisation processes, there is no sound empirical evidence base on the risk and protective factors for violent extremism and much research is not fit for practice. Day-to-day risk assessment and management of individuals deemed to be a potential risk to national security forms a core component of counter-terrorism. Each phase of counter-terrorism risk assessment and management requires state-of-the-art science for the identification of putative risk and protective factors, and to understand how such factors are functionally linked to violent extremism. This thesis provides a unique contribution to these research endeavours in several important ways. First, in order to explain why individuals radicalise, we have to turn our focus towards those risk factors and underlying mechanisms, which explain why and how certain individuals come to develop extremist propensities. Thus, this thesis’ main aim is to study risk and protective factors for the development of violent extremist propensities. Second, terrorism studies is over-reliant on secondary data. By conducting two unique large-scale nationally representative general population surveys, this thesis contributes towards establishing a robust empirical knowledge base. These are one of the first such surveys conducted within the field of violent extremism research. Third, radicalisation trajectories and engagement in violent extremism are characterised by complex constellations of risk as well as protective factors. Risk factors for one risk specification may not equally apply to others and the conditional and contextual nature of various factors need to be taken into consideration, which necessitates more complex analyses of patterns of relationships. This thesis draws on a range of structural equation models, conditional mediation models and interaction analyses, which allow for a better understanding of the underlying mechanisms and complex configurations of various risk and protective factors. The analytical designs embedded throughout this thesis are some of the first to test such interactions in an empirical manner. Fourth, this thesis uses an integrative framework which examines not just risk but also protective factors for violent extremism and draws on a wide range of validated theories from different disciplines to strengthen the explanation of relationships between factors. By utilising models with several risk/protective factors, this thesis overcomes some of the 'problem of specificity', as it delivers plausible answers as to why the vast majority of individuals, who are experiencing particular conditions or grievances do not develop violent extremist intentions. Such research designs may be able to identify those factors that can inform prevention and intervention programs. Fifth, radicalisation is a complex and multifaceted process with diverse pathways and outcomes to it. This inherent complexity renders radicalisation, as a construct, difficult to operationalise. A key part of conducting quantitative research is the development of adequate and validated instruments. Thus, by developing and validating psychometrically sound instruments, this thesis contributes towards rigorous quantitative research on violent extremism. This thesis addresses these issues through a number of novel research designs. First, I conduct a systematic review and synthesise the existing evidence on quantitative risk and protective factors for different radicalisation outcomes. However, several gaps as well as conceptual and methodological issues are identified, which are addressed in the following chapters. Second, I conduct a German nationally representative survey on violent extremism, and I apply structural equation modeling to employ a conceptually integrated approach to studying the individual and environmental-level determinants of differential vulnerability to extremism. The findings demonstrate the profound effect of person-environment reciprocity and, thereby, highlight key individual, developmental and social mechanisms involved in the development of extremist propensities. Increasingly, we are witnessing a seeming convergence between belief in conspiracy theories and ideological extremes. However, there is a dearth of empirical research on the relationship between conspiracy beliefs and violent extremism. Therefore, third, this thesis conducts a unique quantitative analysis on this relationship and the findings highlight the contingent effects of risk and protective factors, which are defined as ‘interactive’ or ‘buffering’ protective factors. This has major implications in regard to prevention strategies of ‘at-risk’ populations. Fourth, based on a large-scale UK nationally representative survey, I develop and validate a novel psychometric tool to measure individuals’ misogynistic attitudes. Fifth, recent incidents have demonstrated that misogynistic beliefs can lead to acts of mass violence. This thesis provides the first survey-based study on the relationship between misogyny and violent extremism by examining the underlying mechanisms and contingent effects linking misogyny to (extremist) violence. Collectively, the dissertation’s results demonstrate that multiple factors likely contribute to individual pathways into violent extremism. No single risk or protective factor exists that can explain its genesis. This has significant implications for practice and policy. Preventing and countering violent extremism (P/CVE) programs must take account of the constellation of multiple factors that interact with (and sometimes enable or disable one another) rather than solely focusing upon single risk factors. These findings stress the need to implement evidenced based prevention and interventions programs, which have to address these risk factors early on, before they properly take hold and become so deeply ingrained that they are almost intractable. Therefore, increased focus of P/CVE interventions should be put on the indirect, long-term and life-course oriented protective factors.
... Finally, the perpetrator's radical, hateful posts on social media, violent fantasies, death threats, and glorification of severe acts of violence can be interpreted as a form of selfcommitment (Böckler et al. 2018;Collins 2014), which may have further pushed her to carry out the attack. Perhaps she got herself into a pretty pickle having to put her words into action. ...
In the early hours of June 8, 2017, a Weis Market employee in Tunkhannock, Pennsylvania, shot three co-workers and herself. Shortly before the shooting, the perpetrator uploaded vast amounts of digital material, so-called legacy tokens, to the Internet. She daily frequented various forums and social media platforms and produced large amounts of written, audio, and video content, some of which macabre and explicit. This content revealed her desire for fame and attention and a fascination for other rampage killers, both characteristics of fame-seeking rampage shooters. In this study, we analyze the perpetrator's legacy tokens and shed light on her biography, family relationships, personal crises and grievances, and recurring themes in her communication. The perpetrator was particularly preoccupied with a fictional group she founded called “Ember's Ghost Squad”; death and dying; depression and suicidal tendencies; gender identity and sexuality; violent fantasies; previous rampage killers (esp. the Columbine shooters); and grandiose fantasies, narcissistic tendencies, and a desire for fame. We present hypotheses regarding drives and motives that led to the shooting and conclude that the core of severe targeted violence lies in an enduring maladaptive coping with individual grievances, regardless of the narratives they are embedded in. Particularly, fame seeking as a means to identity building and stabilization of self-worth offers a valuable explanatory approach, which can also be helpful from a risk assessment perspective. Highlighting some challenges that arose in data mining and analysis, we discuss practical implications and recommendations for the early detection of intent to commit a violent act.
... Further comparison is warranted to address some of the shortcomings in the earlier mentioned analyses. This article compares 115 public mass murderers and 71 lone-actor terrorists across a range of features beyond demographics and event characteristics [23], incorporating a wider set of behaviors and experiences beyond mental health histories, grievances, and strain [24] whilst also utilizing a large-n dataset [25]. We ask: what (dis)similarities are observable across both offender types and what are the implications for lawenforcement? ...
Full-text available
This article adds to the growth in data‐driven analyses seeking to compare samples of violent extremists with other violent populations of interest. While lone‐actor terrorists and public mass murderers are frequently treated as distinct offender types, both engage (or attempt to engage) in largely public and highly publicized acts of violence and often use similar weapons. This article investigates the (dis)similarities between both offender types. We use a series of bivariate and multivariate statistical analyses to compare demographic, psychologic and behavioral variables across 71 lone‐actor terrorists and 115 public mass murderers. The results show little distinction in sociodemographic profiles, but significant differences in (a) the degree to which they interact with co‐ideologues (b) antecedent event behaviors and (c) the degree to which they leak information before the attack. Overall, our data inform the emerging idea that lone‐actor terrorists and public mass shooters are not distinct offender types. There is more that unites them than divides them. Although the over‐arching focus of our results are on the few variables that distinguish them, the vast majority (80%+), of the 180+ variables showed no significant difference. We discuss implications for threat assessment and management in the context of these results.
... Dies steht durchaus im Einklang mit der internationalen Forschung zu Radikalisierungsprozessen und Kriminalitätsursachen, die davon ausgehen, dass eine Entwicklung in die extremistische und fremdenfeindliche Straftat biografische Vorläufer hat, die in der Regel auf ein dynamisches Zusammenspiel von negativen individuellen, sozialen und gesellschaftlichen Faktoren zurückzuführen sind (vgl. z.B.Böckler et al., 2018;Schmid, 2013).Insofern hat eine Radikalisierung, die von der Entwicklung menschenfeindlicher Einstellungen bis zu einer rechtsextremen Straftat reicht, viele Pfade und Einflussfaktoren im Kontext der jeweiligen Milieus und Lebensumstände von radikalisierten Personen. Das Projekt hat mit Blick auf bereits vorhandene Studien und wissenschaftlich einschlägige Modelle diese Faktoren genauer untersucht und geprüft. ...
The link between mental health difficulties and terrorist behaviour has been the subject of debate for the last 50 years. Studies that report prevalence rates of mental health difficulties in terrorist samples or compare rates for those involved and not involved in terrorism, can inform this debate and the work of those responsible for countering violent extremism. To synthesise the prevalence rates of mental health difficulties in terrorist samples (Objective 1—Prevalence) and prevalence of mental health disorders pre‐dating involvement in terrorism (Objective 2—Temporality). The review also synthesises the extent to which mental health difficulties are associated with terrorist involvement compared to non‐terrorist samples (Objective 3—Risk Factor). Searches were conducted between April and June 2022, capturing research until December 2021. We contacted expert networks, hand‐searched specialist journals, harvested records from published reviews, and examined references lists for included papers to identify additional studies. Studies needed to empirically examine mental health difficulties and terrorism. To be included under Objective 1 (Prevalence) and Objective 2 (Temporality), studies had to adopt cross‐sectional, cohort, or case‐control design and report prevalence rates of mental health difficulties in terrorist samples, with studies under Objective 2 also needing to report prevalence of difficulties before detection or involvement in terrorism. For Objective 3 (Risk Factor) studies where there was variability in terrorist behaviour (involved vs. not involved) were included. Captured records were screened in DisillterSR by two authors. Risk of bias was assessed using Joanna Briggs Institute checklists, and random‐effects meta‐analysis conducted in Comprehensive Meta‐Analysis software. Fifty‐six papers reporting on 73 different terrorist samples (i.e., studies) (n = 13,648) were identified. All were eligible for Objective 1. Of the 73 studies, 10 were eligible for Objective 2 (Temporality) and nine were eligible for Objective 3 (Risk Factor). For Objective 1, the life‐time prevalence rate of diagnosed mental disorder in terrorist samples (k = 18) was 17.4% [95% confidence interval (CI) = 11.1%–26.3%]. When collapsing all studies reporting psychological problems, disorder, and suspected disorder into one meta‐analyses (k = 37), the pooled prevalence rate was 25.5% (95% CI = 20.2%–31.6%). When isolating studies reporting data for any mental health difficulty that emerged before either engagement in terrorism or detection for terrorist offences (Objective 2: Temporality), the life‐time prevalence rate was 27.8% (95% CI = 20.9%–35.9%). For Objective 3 (Risk Factor), it was not appropriate to calculate a pooled effect size due the differences in comparison samples. Odds ratios for these studies ranged from 0.68 (95% CI = 0.38–1.22) to 3.13 (95% CI = 1.87–5.23). All studies were assessed as having high‐risk of bias which, in part, reflects challenges conducting terrorism research. This review does not support the assertion that terrorist samples are characterised by higher rates of mental health difficulties than would be expected in the general population. Findings have implications for future research in terms of design and reporting. There are also implications for practice with regards the inclusion of mental health difficulties as indicators of risk.
The legacy of the 1999 Columbine School shooting has resulted in increased political elements in subsequent shootings and the line between these school shooters and terrorists has blurred. Current research comparing terrorists and school shooters has largely focused on the similarities between the perpetrators using largely qualitative methods. With the behavioural and subsequent economic impacts of terrorism having been previously identified, this paper investigates if these behavioural changes and impacts are present following school shootings. Through the use of a logit regression of historical school shooting data, we find evidence that support our theories that school shootings cause fear and change consumer behaviours.
Amok and terror are rare events, but they are all the more attention-grabbing because they are regularly accompanied by high numbers of victims. What is the probability of a rampage? Who are the perpetrators? Can such acts be prevented?
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The term "Lone Actor" has been applied to a variety of violent individuals who are thought to act out of ideological motivations using terrorist tactics. So far, much of the research is U.S.-based. There is an empirical vacuum of Lone Actor violence in Europe and a conceptual gap in how these acts may be understood as a variation of homicidal behavior. We examine and compare characteristics of European Lone Actors to European "common" homicide offenders. Lone Actor terrorists constitute a heterogeneous group that is similar to homicide offenders but differs in terms of substance use, weapon use, and target. These findings may be understood in the context of instrumental versus expressive aims.
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The case of the Frankfurt Airport attack in 2011 in which a 21-year-old man shot several U.S. soldiers, murdering 2 U.S. airmen and severely wounding 2 others, is assessed with the Terrorist Radicalization Assessment Protocol (TRAP-18). The study is based on an extensive qualitative analysis of investigation and court files focusing on the complex interconnection among offender personality, specific opportunity structures, and social contexts. The role of distal psychological factors and proximal warning behaviors in the run up to the deed are discussed. Although in this case the proximal behaviors of fixation on a cause and identification as a “soldier” for the cause developed over years, we observed only a very brief and accelerated pathway toward the violent act. This represents an important change in the demands placed upon threat assessors. (PsycINFO Database Record (c) 2016 APA, all rights reserved)
Full-text available
An open source sample of 111 lone-actor terrorists from the United States and Europe were studied through the lens of the Terrorist Radicalization Assessment Protocol (TRAP-18). This investigative template consists of 8 proximal warning behaviors and 10 distal characteristics for active risk management or active monitoring, respectively, by national security threat assessors. Several aspects of criterion validity were tested in this known outcome sample. Seventy percent of the terrorists were positive for at least half or more of the indicators. When the sample was divided into Islamic extremists, right-wing extremists, and single-issue terrorists, there were no significant differences across all 18 indicators except for 4. When the sample was divided according to successful versus thwarted attackers, the successful attackers were significantly more fixated, creative, and innovative, and failed to have a prior sexually intimate pair bond. They were significantly less likely to have displayed pathway warning behavior and be dependent on a virtual community of likeminded true believers. Effect sizes were small to medium (ϕ = 0.190–0.317). The TRAP-18 appears to have promise as an eventual structured professional judgment risk assessment instrument according to some of the individual terrorist content domains outlined by Monahan (2012, 2016).
Over the past 5 years, Europe has witnessed an increasing number of attacks by "lone actors," whose definition and classification presents challenges to the existing premises of violence research. These cases appear to combine elements from both rampage killings (school shootings) and terrorism. Research has to date treated school shootings and lone-actor terrorism as distinct phenomena, although no clear and unequivocal definitions have been formulated for either. In terms of execution and developmental path, school shooters and lone-actor terrorists appear to have a great deal more in common than previously thought. Against the background of the current state of research, we derive hypotheses about the differences and similarities in the genesis of both phenomena. In relationship to execution, this applies to the planned mode of assassination and the communicative significance attached to both phenomena. In connection with the development path, we find that similar processes of progressive cognitive transformation (toward a polarized and violent interpretative framework) occur in a context of experienced grievances and crises, whereby both groups tend to exhibit functional processing of reality. Processes of identification with biographically and culturally compatible worldviews and interpretative frameworks lead to a redefinition of the perpetrator's self-concept, and in turn to cognitive escalation and changes in behavior. The path toward violent action is supported by social mechanisms arising out of the necessity to keep this cognitive and behavioral escalation process secret. Finally, similar trigger events are observed for both phenomena. In this context, we describe school shootings and acts of terrorism as demonstrative targeted violence.
In some recent cases of lone-actor terrorism, there is evidence the subject acted impulsively, often in response to a triggering event which contained a loss and humiliation. Evidence suggests the subjects acted precipitously, despite planning and preparation carried out in the preceding weeks or months, and their attacks failed to include the often considerable preparation that had been done. The pathway became a runway. The authors recommend the traditional assessment of impulsivity in persons of concern for lone acts of terrorism, as well as other proximal warning behaviors for targeted violence. Both indirect and direct assessment guidelines are proposed, with an emphasis upon self-report, psychological testing, collateral data gathering, and historical records.
The standardized, indicated school-based prevention program “Networks Against School Shootings” combines a threat assessment approach with a general model of prevention of emergency situations in schools through early intervention in student psychosocial crises and training teachers to recognize warning signs of targeted school violence. An evaluation study in 98 German schools with 3,473 school staff participants (Mage = 46.2 years) used a quasi-experimental comparison group design with three measurement points (pre, post, and 7 months followup) with schools randomly allocated to implementation conditions. The study found increases in teachers' expertise and evaluation skills, enhanced abilities to identify students experiencing a psychosocial crisis, and positive secondary effects (e.g., teacher–student interaction, feelings of safety).
Zusammenfassung Am Beispiel jugendlicher Wiederholungstäter führt der Beitrag das Konzept der Gewaltkarriere ein und demonstriert dessen explikativen Wert für die Biographieforschung und Kriminalsoziologie. In handlungstheoretischer Hinsicht kritisiert er eine ausschließliche Orientierung am Modell des rational handelnden und stets handlungsfähigen Akteurs. Er unterscheidet zwischen Verlaufskurven des Erleidens familiärer Gewalt und Missachtung einerseits und Handlungsschemata der Gewaltausübung andererseits. Nach der Rekonstruktion einer ersten Phase von Gewaltkarrieren, die von Erfahrungen der Viktimisierung in der Familie geprägt ist, aber auch Vorboten einer gewaltsamen Rückgewinnung von Handlungsmacht und Anerkennung aufweist, arbeitet der Beitrag im Rekurs auf den Begriff der epiphanischen Erfahrung biographische Wendepunkte heraus, die den identitätsstiftenden Umschlag von der Opfer- in die Täterrolle herbeiführen. Schließlich werden drei wesentliche Aspekte gewalttätiger Handlungsschemata aufgezeigt, die für eine zweite Phase von Gewaltkarrieren charakteristisch sind: gewaltaffine Interpretationsregimes, mit deren Hilfe sich die lange ungeklärte Frage beantworten lässt, wie familiäre Gewaltzusammenhänge in jugendliche Lebenswelten hinein transferiert werden; intrinsische Gewaltmotive, die aus berauschenden Erfahrungen der Gewaltausübung hervorgehen und zu einer Verselbständigung entsprechender Handlungsmuster führen; und Gewaltmythologien, mit denen die Jugendlichen die Gewaltsamkeit normativ auszeichnen und in ihren Wirkungen glorifizieren.