Robert J. B. Lehmann

MSB Medical School Berlin | MSB · Department of Psychology

Possession and distribution of child sexual abuse material (CSAM) is a serious criminal offence facilitated by online technologies. To prevent, investigate, and treat online CSAM offending, comprehensive knowledge of potential risk factors for these crimes is required. Given the large body of relevant research, a systematic overview of the risk fac...

Darknet forums dedicated to child sexual abuse material (CSAM) attract thousands of users interacting with each other through online communications. Given finite resources, law enforcement agencies seek ways to effectively prioritise their investigative efforts by identifying key-players that are central to the forum community. For the identificati...

In their influential paper Wurtele et al. (2014) investigated the degree to which individuals within the general population (N = 435) express sexual interest in children. In the male population of their study (n = 173), about 6% showed a propensity to engage in sexual activity with a child. Based on a German general population sample consisting of...

People with pedophilia (PWP) can deal with their sexual desires by relieving sexual arousal without sexually exploiting children. Study 1 investigated whether public reactions toward nonoffending pedophilic men are affected by their strategies to relieve sexual arousal (non-sexual pictures vs. child sex dolls) or to reduce their sex drive via testo...

Risk assessment plays an important role in forensic mental health care. The way the conclusions of those risk assessments are communicated varies considerably across instruments. In an effort to make them more comparable, Hanson, R. K., Bourgon, G., McGrath, R., Kroner, D. D., Amora, D. A., Thomas, S. S., & Tavarez, L. P. [2017. A five-level risk a...

Background: The darknet hosts an increasing number of hidden services dedicated to the distribution of child sexual abuse material (CSAM). Given that by contributing CSAM to the forum members subject themselves to criminal prosecution, questions regarding the motivation for members contributing to darknet CSAM forums arise. Objective: Building on i...

Zusammenfassung: Unter ritueller sexueller Gewalt werden Formen organisierten sexuellen Missbrauchs verstanden, die ideologisch geprägt sind und von mehreren Täter_innen über längere Zeiträume ausgeübt werden. Üblicherweise wird in Verbindung mit dem Phänomen von Prozessen absichtlicher Persönlichkeitsspaltung, induzierten Amnesien und Instruierbar...

Gray et al.’s (2003) Sexual Fantasy Questionnaire (SFQ) is becoming an increasingly used self-report measure of sexual fantasy use. The current study analyzed the factorial structure and construct validity of the behavioral items of the SFQ using a nomological network of other sexuality-related measures in a large German-speaking sample (N = 846)....

This study combined research on human mate preferences and attraction to physical and psychological features of children. Specifically, we used the Ideals Standards Model (ISM; Fletcher & Simpson, 2000; Fletcher et al., 1999) as a conceptual framework to investigate the sexual relevance of adult and child sex cues within the general population. A s...

Prevention of the consumption of online child sexual exploitation material presents society with a host of new challenges and is a priority of the European Union (EU). Alongside the identification and prosecution of individuals who use child sexual exploitation material, there is a strong desire to prevent these offences before they occur. Due to t...

Wissenschaftlich fundierte Einschätzungen zur Rückfälligkeit von Straftätern können grundsätzlich mit zwei methodischen Ansätzen vorgenommen werden. Der nomothetische Ansatz liefert eine auf gruppenstatistischen Erkenntnissen basierende Einschätzung und erfolgt zumeist mit standardisierten Instrumenten. Der klinisch-idiographische Ansatz orientiert...

Diagnosing pedohebephilia is fraught with obstacles given the tabooed nature of this sexual preference. The viewing reaction time effect (VRT) provides a non-intrusive indirect measure of sexual interest in minors. In forensic populations, the ability of the difference between the latencies while viewing child and adult sexual stimuli (VRT index) t...

To date, the possession of purely text-based child sexual exploitation material, in contrast to photographic and videographic depictions, is not punishable in Germany. For the first time, the current article shows to what extent stories from a so-called girl lover forum on the darknet address sexualized violence against children. Based on a textual...

By routing traffic through a random combination of servers worldwide, the darknet obfuscates the identity of its users, making it an attractive medium for journalists, dissidents, and individuals committing crimes. Since 2008, access to the darknet has been facilitated by the The Onion Router (TOR) browser, bringing the darknet within reach of an i...

There are multiple ways to report risk scale results. Varela et al. (2014) found that Static-99R results were interpreted differently by prospective jurors based on risk level (high vs low) and an interaction between risk level and risk communication format (categorical, absolute estimate, and risk ratio). We adapted and extended Varela et al.'s (2...

Zusammenfassung Herstellung, Besitz und Verbreitung von kinderpornografischem Material (besser „child sexual exploitation material“, CSEM) stellt in Deutschland einen Straftatbestand dar und ist stark im öffentlichen Fokus. Laut Bundeskriminalamt haben sich die aufgedeckten Straftaten in diesem Bereich in den letzten Jahren dramatisch erhöht. Nach...

Zusammenfassung Der Konsum von Missbrauchsabbildungen hat sich im Hellfeld in den letzten Jahren immer wieder verdoppelt. Dieses erhöhte Fallaufkommen stellt Polizei, Bewährungshilfe und forensische Therapeuten vor eine Vielzahl neuer Herausforderungen. In diesem Beitrag sollen daher aktuelle theoretische Modelle und empirische Erkenntnisse dargest...

Due to legislative changes in Germany, there has been an increasing expansion of social-therapeutic facilities for juvenile offenders over the past 15 years. Social therapy comprises an eclectic mix of psychotherapeutic, educational, vocational, and recreational measures in a milieu-therapeutic setting to reduce recidivism of high-risk violent and...

The Screening Scale of Pedophilic Crime Scene Behavior (SSPC) is a seven-item structured rating scale assessing pedophilic sexual arousal. In the current study, we cross-validated the scale’s convergent validity using multiple measures of sexual interest in children (clinical diagnosis of pedophilia, the high fixation/low social competence type of...

Homelessness is a serious social and health problem that is very important for community care and problem-oriented policing (POP). As this vulnerable population is difficult to reach, sound empirical data on psy-chosocial characteristics and contacts with the police are rare. This article reports a study of people experiencing homelessness from Ber...

Im Kapitel werden die Grundlagen zweier übergreifender deliktpräventiver Straftäterbehandlungsmodelle dargestellt. Anhand eines Fallbeispiels wird das Behandlungsvorgehen aus der Perspektive des Risk-Need-Responsivity und des Good Lives Modells überblicksartig beschrieben und kurz auf die Evidenzbasierung beider Ansätze sowie deren Vereinbarkeit ei...

Except for pedophilia, little is known about public attitudes towards paraphilias and psychological conditions that are considered risk factors for sexual offending. In the present study we sought to compare the stigma attached to pedophilia with attitudes towards sexual sadism and antisocial tendencies (Study 1, N = 720) and with attitudes towards...

Incorporating measures of prison behavior into risk assessment and management procedures may assist in treatment planning, risk monitoring, and decision-making. A behavior rating scale was used to assess prison officers’ observations on externalizing, internalizing, and adaptive behavior in a sample of 277 sexual and violent offenders in correction...

Incorporating measures of prison behavior into risk assessment and management procedures may assist in treatment planning, risk monitoring, and decision-making. A behavior rating scale was used to assess prison officers’ observations on externalizing, internalizing, and adaptive behavior in a sample of 277 sexual and violent offenders in correction...

Clinicians and theorists have often proposed the two psychopathic subtypes of “primary” and “secondary” psychopathy, with recent research indicating some empirical support for both psychopathy subtypes, though the findings across studies are far from uniform. For the current study, latent profile analysis was used to investigate if homogeneous late...

The Wilson Sex Fantasy Questionnaire (WSFQ) assesses the use of 40 specific sexual fantasies, which are grouped into four overarching themes (Intimate, Exploratory, Impersonal, and Sadomasochistic). It also includes two items that reflect characteristics associated with children. Since sexual fantasies are a key factor in sex offender treatment, th...

Measures of current behavior are rarely incorporated into risk assessment. Therefore, the current study used a behavior rating scale to assess prison officers' observations of inmates prison behavior and examined the contribution of these ratings for risk assessment. Prison officers rated 272 sexual and violent offenders in three different correcti...

Für die kriminalprognostische Begutachtung von Rechtsbrechern werden unterschiedliche methodische Ansätze diskutiert, die verschiedenen wissenschaftstheoretischen Modellen folgen (nomothetische/idiografische Urteilsbildung). Beide haben Vorzüge und Begrenzungen. Gesetzlich obliegt die Auswahl der im Einzelfall geeigneten methodischen Strategie letz...

Over the last decades several attempts in developing incrementally valid risk indicators above and beyond standard actuarial and dynamic risk assessment instruments have been undertaken without much success. The current review will summarize current developments regarding the validity of detailed crime scene analysis for forensic assessments of sex...

Zusammenfassung Derzeit gibt es nur wenig Forschung zu Sexualdelinquenten, die eine Zuwanderungsgeschichte haben und nicht aus dem euroamerikanischen Raum stammen. Es ist daher weitestgehend unklar, ob und, wenn ja, worin sich Täter mit und ohne Migrationshintergrund (MH) hinsichtlich des Delikts, demografischer Charakteristika, spezifischer Tatver...

Die vorliegende Arbeit befasst sich mit der Fremdbeurteilung von Inhaftierten durch den allgemeinen Vollzugsdienst (AVD). Verhaltensbeobachtungen durch den AVD gehören vielerorts bereits zum vollzuglichen Alltag (z. B. im Rahmen von Vollzugsplankonferenzen), erlauben sie doch potenziell wertvolle Einblicke „hinter die Kulissen“, die dem therapeutis...

Due to unobtrusiveness and ease of implementation, viewing time (VT) measures of sexual interest in children have sparked increasing research interest in forensic contexts over the last two decades. The current study presents two meta-analyses of VT measures adapted to assess pedophilic interest to determine their discrimination between sexual offe...

Die Beurteilung der Kriminalprognose eines Rechtsbrechers ist ein komplexer Prozess der zielgerichteten Informationsgewinnung und ihrer integrativen Bewertung. Ihr Zweck muss sich dabei nicht auf die bloße Einschätzung der Rückfallwahrscheinlichkeit eines Rechtsbrechers beschränken. Er kann auch darin bestehen zu verstehen, warum der Rechtsbrecher...

Nominal risk categories for actuarial risk assessment information should be grounded in non-arbitrary, evidence-based criteria. The current study presents numeric indicators for interpreting one such tool, the Risk Matrix 2000, which is widely used to assess the recidivism risk of sexual offenders. Percentiles, risk ratios, and 5-year recidivism ra...

Research consistently shows that structured, actuarial approaches to recidivism prediction are more accurate than (unstructured) professional judgment. Therefore, the purpose of this chapter is to discuss the strengths of actuarial risk assessment. First, we will provide greater discussion of ways to conceptualize risk factors that may be included...

The aim of the current study was to enhance the assessment and predictive accuracy of risk assessments for sexual offenders by utilizing detailed crime scene analysis (CSA). CSA was conducted on a sample of 247 male acquaintance rapists from Berlin (Germany) using a nonmetric, multidimensional scaling (MDS) Behavioral Thematic Analysis (BTA) approa...

PurposeContinued debate surrounds whether or not offender profiling is a valid practice. Critics have mainly contended that few studies have produced clear, quantifiable, evidence of a link between crime scene actions (A) and offender characteristics (C). Arguing that this is due to a failure to study offender actions as part of a dynamic decision-...

Anliegen der Studie war die Erprobung der diagnostischen Potenziale von Merkmalen des Tatverhaltens, das Täter mit sexuellem Missbrauch von Kindern zeigen, im Hinblick auf Indikatoren für zugrunde liegende pädophile Neigungen und die Entwicklung einer hierauf fußenden Skala. Die Entwicklungsstichprobe bestand aus 113 Fällen des Gutachtenarchivs des...

The inclusion of crime scene behavior in actuarial risk assessment so far is insufficient, unsystematic, and neglecting factors theoretically relevant to sexual recidivism. Therefore, the goal of the current study was to develop a brief actuarial risk scale based on crime scene characteristics. The development sample consisted of data (police datab...

The current study used crime scene analysis (CSA) to identify the psychological characteristics of child molesters and examined the contribution of these behavioral themes for sexual offender risk assessment. CSA was conducted on a sample of 424 cases of child sexual abuse in Berlin (Germany) using non-metric Multi-Dimensional Scaling. The analysis...

This study tested 3 decision rules for combining actuarial risk instruments for sex offenders into an overall evaluation of risk. Based on a 9-year follow-up of 940 adult male sex offenders, we found that Rapid Risk Assessment for Sex Offender Recidivism (RRASOR), Static-99R, and Static-2002R predicted sexual, violent, and general recidivism and pr...

The current study seeks to advance the faceted multidimensional scaling (termed FMDS) procedure used in much of the investigative psychology research. To this end, recent research on street robbery by Goodwill and colleagues will be utilised to illustrate the effectiveness of a facet scale method for offender profiling. Four FMDS themes of street r...

The current study sought to improve the predictive accuracy of sexual recidivism using the Static-99 risk assessment tool by the addition of detailed crime scene analysis (CSA). CSA was carried out using a Behavioral Thematic Analysis (BTA) approach, the gold-standard in CSA. BTA was conducted on a sample of 167 stranger rape cases using nonmetric...

According to the phenomenon of hindsight bias, once people know the outcome of an event, they tend to have biased estimates of the probability that the event would have occurred. In this study, we investigated whether hindsight bias affected judgements about the legitimacy of lethal force decisions in police shooting incidents for counter-terrorism...

The basis of this study was a census of all offenses of sexual assault and sexual abuse that were reported to the Berlin police between 1994 and 1999 (N = 2,446). The purpose was to analyse the particularities of elderly offenders (60 years or older, n = 68) compared to the 273 juvenile and the 2,105 younger adult offenders with regard to prior off...

This study compared a sample of 273 juvenile (aged 14 to under 18), 178 adolescent (aged 18 to under 21) and 273 adult (older than 20 years) male sex offenders modus operandi (or MO, the way in which they committed their offenses), frequency of recidivism and predicted recidivism via the static-99. In terms of the frequencies of the MO aspects we f...