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1Indiana University Purdue University Indianapolis, Indianapolis
Kenna Quinet, Indiana University Purdue University Indianapolis (IUPUI), School of Public and
Environmental Affairs, 801 W. Michigan St., BS SPEA 4064, Indianapolis, IN 46202
Prostitutes as Victims
of Serial Homicide: Trends
and Case Characteristics,
This work includes a count of solved serial murder cases in the United States from
1970 to 2009. The number of serial murder cases has declined; the likelihood that
a victim is a female has increased somewhat and although the numbers of all types
of serial murder victims has declined, when a case occurs, victims are increasingly
likely to be prostitutes, particularly female prostitutes. U.S. serial murder cases with
prostitute victims accounted for 32% of all U.S. serial murder cases involving female
victims only, 1970-2009. However, the proportion of solved cases involving female
prostitute victims only increased across the study period from 16% during 1970-1979
to a high of 69% during 2000-2009. Prostitute killers amass a greater average number
of victims than do nonprostitute killers and when analyzed by decade, those who
kill primarily prostitutes, kill for slightly longer periods of time. The implications of
findings for prevention and investigation efforts are discussed.
serial murder, prostitutes, victim gender, victim counts, active periods
Recently, more scientific attention has been paid to the quantification and nature of
serial murder cases in the United States. As a result, we now have more accurate esti-
mates of serial murder offenders, their offending patterns, and the number of people
victimized. (Aamodt, Moberg, Nash, Pendleton, Hommema, & Walker, 2007; Aamodt,
Henriques, & Hodges, 2008; Egger, 1990, 2002, 2003; Fox & Levin, 1985, 2005;
Godwin, 2008; Hickey, 2006; Kraemer, Lord, & Heilbrun, 2004; Landrigan & Canter,
2001; Missen, 2000; Quinet, 2007; Rossmo, 1995). Precise analysis of who falls vic-
tim to this crime and why remains a challenging frontier in serial homicide research.
A lack of consistent and reliable estimates of the nature of serial murder victims and
how, if at all, victimology has changed over time thwarts efforts designed to curtail
cases with high serial murder victim counts. Ritter’s (2002) call to serial murder
researchers recommended that scholars conduct research that aids in prevention, inter-
vention, and investigation of cases and, thus, we should focus our limited resources
on the highest risk groups, but who are they?
To help address these important questions, this study gathers data on cases of U.S.
serial murder, 1970-2009. These data are used to assess change in the number of serial
murder cases in the United States, the gender distribution of victims over time, trends
in the number of prostitute and nonprostitute cases as well as average victim counts and
lengths of active killing periods by decade. Clarification of serial murder risk for pros-
titutes is important given the established higher risk of homicide in general for female
prostitutes (Brewer et al., 2006; Salfati, 2009; Salfati, James, & Ferguson, 2008), the
wide ranging estimates of U.S. prostitute serial homicide victims in the literature, and
the possibility that serial murders of victims perceived as being of lower social status
have been undercounted (S. Egger, 2002; Quinet, 2007).
Existing Serial Murder Data
One of the challenging issues facing studies of serial homicide is the difficulty of
gathering information about such cases. Nonetheless, several researchers have taken
up the challenge. Table 1 presents a summary of the major existing academic serial
murder databases. An inspection of Table 1 finds variation in the amount and nature
of the information collected, as well as the time period covered, the geographic areas
covered, the inclusion of solved versus unsolved cases, and the extent to which there
was a focus on a certain type of victim. Only S. Egger (2002) focused on prostitute
cases. Egger also suggested (2003) that 65% of serial murder victims are female and
“nearly 78% of female victims of serial murderers are prostitutes” (2003, p. 49).
Although Egger’s work (as cited in K. Egger, 2002) focused on newspaper accounts
of serial murder cases involving prostitute victims from 1991 to 1993 (n = 21), most
other studies of serial murder victims have created broader descriptions of the nature
of victims, and prostitutes are part of a category that would also include the homeless,
transients, and runaways.
Rossmo’s (1995) data were gathered for his dissertation and included 225 killers,
with (three or more victims) from 193 cases (1835-1993, U.S. and non-U.S. cases,
solved and unsolved) with a focus on detailed information on the location of serial
murder (e.g., encounter, attack, murder, and body disposal site; see Rossmo, 1995, in
Table 1). Rossmo’s count for known victims was 1,983 and he notes that as many as
4,213 victims were suspected to have been murdered by his sample of offenders. To test
Table 1. Selected U.S. Academic Serial Murder Databases
area covered Solved vs. unsolved
Number of cases/
offenders Number of victims
S. Egger cited in K. Egger
(2002, p. 90)
newspaper accounts of
cases involving prostitute
U.S. cases “unsolved or
21 cases 198
Rossmo (1995) FBI Investigative Support
newspaper search file
1835-1993 U.S. and Non-
Solved and unsolved
cases for 225,
solved only cases
for analysis of 15
193 cases; subset
of analysis for
1,983 victims for
178 victims for subset
of 15 offendersb
K. Egger (2002), S. Egger
Media coverage, interviews,
and other scholarly work
1900-1999 U.S. and Non-
Solved and unsolved
236 U.S. cases
Fox & Levin (2005) Media coverage, interviews,
and other scholarly work
1900-1999 U.S. cases Solved cases 494 cases including
Hickey (2006) Media coverage, interviews,
and other scholarly work
1800-2004 U.S. cases Solved cases 367 cases 2,760-4,340 known and
Aamodt et al. (2007, 2008),
M. Aamodt (personal
Media coverage, interviews,
and other scholarly work
1564-2007 U.S. and Non-
Solved cases 1,194e offenders 8,273-20,361
Godwin (2008) WA State Homicide
1950-1995 U.S., State of
All but two were
107 offenders 728
a. See S. Egger (2002, p. 90), especially Egger’s definition of serial murder, which varies from that used by most serial murder researchers (most researchers use the three or more
victims definition). Egger defines serial murder, in part, as “one or more individuals (in many cases, males) commit a second murder and/or subsequent murders” (S. Egger, 2002,
p. 5) and this may in part explain some differences in some of his findings.
b. Rossmo presented detailed analysis of victim characteristics for a subset of 178 victims of 15 offenders who killed five or more victims and gender breakdown was available for the
subset only. The definition of serial murder used for inclusion in the dataset of 225 offenders was three or more victims.
c. Both sources collectively refer to a dataset covering U.S. and worldwide serial murder cases, but the number of offenders and victims as well as the years covered pertaining to
the authors’ finding that “nearly 78% of female victims of serial murderers are prostitutes” (2003, p. 49) is unclear.
d. Personal communication with Aamodt (2008, 2009) included updated numbers from his original presentations.
e. Aamodt et al. (2008) presented detailed analysis on victim characteristics for a subset of 1,194 offenders out of 1,201 total offenders in his database.
his hypotheses regarding offender residence and crime locations, Rossmo conducted
detailed analysis on a subset of serial murder offenders (n = 15) who had killed five or
more victims. These 15 offenders killed 178 victims and Rossmo found 72.5% were
female and 40 of the 178 victims (22.5%) were engaging in prostitution (Rossmo,
1995). From his larger dataset of 225 killers, Rossmo’s other major victim location/
activity categories included 31% of victims (n = 55) at home at the time of the serial
murder and 22% walking or jogging. Thus, for Rossmo, the second most frequent victim
activity/type was prostitution. The category of “at home” could refer to any number of
different victim types—elderly, young children, random citizens, and so on.
Fox and Levin (2005), defining serial killers as those who killed four or more vic-
tims, presented information on 494 U.S. serial killer cases active from 1900 to 1999
(with 558 total offenders). Fox and Levin found that these offenders generated a mini-
mum of 3,850 homicides and a possible upper limit of 5,650 (p. 32). Fox and Levin
also provided an estimate of the number of killers active in each decade from 1900 to
1999. Since a series of homicides may overlap decades, killers are categorized by Fox
and Levin by decade midpoints as opposed to the decade the killing started (or ended,
or was discovered). If a killer began in 1978 and ended in 1996, Fox and Levin would
calculate the midpoint at 1987 and that offender would be counted in the 1980s. Using
this strategy, Fox and Levin found that the 1980s saw well over 150 different cases and
found less than 100 cases for the decade of the 1990s (although it is assumed that some
cases occurring in the 1990s had yet to be discovered when Fox and Levin published
Fox and Levin (2005) also found that of their male serial killers, 33% chose female
victims and another 12.2% chose prostitute victims. More than 33% of Fox and Levin’s
male offenders’ victims are females as their coding strategy codes by the offender’s
primary target and many of their primary categories can contain female victims (e.g., fam-
ily, children, patients, elderly; p. 39). Of the female serial killers, 2.8% chose female
victims as their primary target and 0.7 chose prostitutes. Calculating from the informa-
tion provided in Fox and Levin’s tables, of the 480 male offenders and 78 female offend-
ers, 27% chose females as their primary targets and 11% chose prostitutes. Again, the
Fox and Levin victim categories are not mutually exclusive, and thus an exact estimate
of the proportion of offenders who chose females or prostitutes is not possible. Using
the Fox and Levin findings, it is estimated that less than 15% of offenders chose pros-
titute victims as their primary target (Fox & Levin, 2005).1 Assuming that most of the
prostitute victims are female (as is the case in other studies), at a minimum 38% of Fox
and Levin’s victims are female (female victims plus most prostitute victims). Since
there are many more females in the other categories, it is assumed that the proportion of
female victims is actually much higher than 38%. As is the case with most other serial
murder data, the primary research question for Fox and Levin was not the proportion of
all cases that involved prostitute victims.
Hickey’s (2006) study of the characteristics of serial murderers and their victims
includes extensive detail on approximately 367 U.S. serial murder cases from 1800 to
2004, 187 of those cases occurring between 1975 and 1995. Hickey’s data include
78 Homicide Studies 15(1)
offenders who were charged with killing three or more individuals (not necessarily
convicted of all charges) and solved cases only (Hickey, 2006). Hickey’s 367 cases of
serial murder generated a victim count range of between 2,760 victims to 4,340 victims
(victim ranges include known and suspected victims).
Regarding female and prostitute victims, Hickey did not specifically code prostitute
cases and ranked the likelihood of certain victims in broader categories. Hickey found
“young females” (p. 152) were the most likely serial killer victims for offenders who
chose strangers and within the category of “young females,” the most likely victim was
a female prostitute. But, the category also included female hitchhikers, students, women
at home, women seeking employment, as well as nurses, models, and waitresses
(p. 154, Table 5.7). Hickey also finds that young women were the most likely victims
of serial killers who killed acquaintances. Hickey speculates that prostitutes are cho-
sen because access to the victim and disposal of the body were easier for the offender
(p. 152). He does not suggest an actual proportion of cases that include prostitute vic-
tims. He does suggest that female prostitutes are the most likely victim category. Hickey
(2006) offers a detailed account of the percentage of 367 of his cases involving female,
male, or both genders of victims. Hickey found that 39% of offenders had female victims
only, 21% male victims only, and 40% of offenders had both male and female victims
(2006, p. 258).
Aamodt and his students have been building a serial murder database for the last
15 years including information on as many as 140 different variables for 1,201 U.S. serial
killers (Aamodt et al., 2007, 2008; M. Aamodt, personal communication, November 4,
2008 and July 13, 2009).2 The Aamodt project, based at Radford University, is begin-
ning to generate preliminary findings and includes detailed offender biographies avail-
able online for 153 serial murder offenders (Aamodt et al., 2007, 2008). The Aamodt
et al. (2008) analysis of serial killers who killed three or more victims, focused on
specific age information for 1,194 serial murder offenders and for those cases he and
his colleagues also coded victim types (e.g., child care, family, criminal/drug dealers,
employees). These types included one large category, “street people,” that included
prostitutes and homeless. M. Aamodt (personal communication, July 13, 2009) found
that prostitutes (n = 149) were the primary victim for 12.5% of serial killers.
Godwin presented crime scene behaviors for 107 U.S. serial murder offenders who
killed 728 victims (2008, p. xv). Godwin’s cases of serial murder with three of more
victims were drawn primarily (75%) from the Homicide Investigation and Tracking
System (HITS) in the state of Washington but also included offenders from 40 other
states. Godwin’s research found that of 726 solved serial murder cases (2 cases were
unsolved), 21% (n = 152) of the 726 solved cases were prostitutes. For Godwin’s sam-
ple, the average number of victims per serial murder cases was 7.5 (p. 51), 67% were
female and 10% (approximately 9 offenders) victimized both males and females.
Although a number of scholarly researchers have been creating serial murder data-
bases over the past 15 years, they vary in their level of detail, the focus of their research
question, the types of cases included (e.g., solved or unsolved cases or both), the time
span covered, the region covered (e.g., Godwin’s sample drawn largely from Washington,
some data worldwide, some United States only) and the definition of serial murder
(e.g., two victims vs. three or more victims). In addition, the data are not publicly
accessible as would be Supplementary Homicide Reports (SHR) data. Thus, to deter-
mine decade-specific trends in the numbers of serial murder cases, the extent to which
those cases have included female victims and what proportion of U.S. serial murder
cases since 1970 have included prostitutes, and more specifically, female prostitutes,
whether or not this proportion has changed over time, and differences in the average
number of victims per case and length of time active for prostitute and nonprostitute
cases, generated a need for primary data collection.
Prostitute homicide research is complicated by the lack of a denominator. Calculating
the rate of serial or even single homicides for prostitutes requires knowing how many
prostitutes there are. One of the only scientific estimates available places the preva-
lence of female prostitution in the United States at .023%, or 23 per 100,000 U.S.
citizens—approximately 84,000 prostitutes as of 1988 (Potterat, Woodhouse, Muth, &
Muth, 1990). The “evanescent” quality of prostitution (Potterat et al., 1990, p. 235)
further complicates the issue. Many prostitutes only work briefly as a prostitute (less
than 1 year), few work more than 5 years, and prostitutes are geographically mobile—
all factors contributing to the challenging pursuit of prostitute homicide rates (Potterat
et al., 1990). Moreover, the likelihood that a prostitute would be among the “missing
missing”—missing persons never reported as missing—is higher for geographically
mobile individuals lacking a stable community social network, as is often the case for
prostitutes (Quinet, 2007).
Church, Henderson, and Barnard’s (2001) study of female street prostitutes in
Scotland found that half of the prostitutes reported some form of violence (e.g., slapped,
kicked, punched, or attempted rape) in the previous 6 months. Brewer et al.’s (2006)
prospective study of female prostitutes working in Colorado Springs, Colorado, from
1967 to 1999 and extrapolations to the United States provides the best available assess-
ment of the extent and nature of female prostitute homicides in the United States. Brewer
et al. (2006) found that 2.7% of all female homicide victims in the United States from
1982 to 2000 were prostitutes, further estimating that 35% of these homicides were the
result of serial homicide offenders. Potterat et al.’s (2004) study of the mortality of
1,633 prostitutes from 1967 to 1999 found higher risks of homicide, suicide, drug and
alcohol-related deaths, accidents, and AIDs deaths (see also Brody, Potterat, Muth, &
Woodhouse, 2005). The Potterat et al. (2004) work also observed that the homicide rate
for female prostitutes was 18 times higher than for women of the same age and race
overall. The workplace homicide rate for female prostitutes (204 per 100,000) is many
times higher than for male taxicab drivers (29 per 100,000) who are generally considered
to be at high occupational risk (Potterat et al., 2004).
Prostitution as an occupation involving sales and service is like other high risk occu-
pations involving working alone, in dangerous areas, at night, and with cash on hand.
80 Homicide Studies 15(1)
Salfati et al. (2008) found that victim property was missing in 14 of 27 cases of pros-
titute homicides (not necessarily serial homicides). Robbery is not likely, however, the
primary motive in serial homicides. Robbery was the sole or primary motive in only
7% of serial murder cases examined by Hickey (2006), with 18% of cases involving
robbery as a motive at least sometimes. Even when property is missing in serial homi-
cides, it is not always clear whether the property was taken for personal gain or as a
Prostitution as an occupation shares some of the attributes associated with higher
crime victimization rates for the homeless. Factors contributing to increased risk for
homeless persons includes lack of shelter (specifically, no desk, no door, no counter to
block an offender), physical proximity to high crime areas, engaging in high risk behav-
iors such as sex work, a history of previous victimization, mental illness, and substance
abuse (Kushel, Evans, Perry, Robertson, & Moss, 2003). Mental illness and sex work
were associated with higher risks of assault among the homeless and marginally homeless
in San Francisco (Kushel et al., 2003). Kushel et al. (2003, p. 2497) refer to the “web of
disabilities,” which make the homeless vulnerable to crime victimization—poor health,
sex work, substance abuse, and homelessness itself. Many of these factors also are
characteristic of prostitution, but given the relative very high rates of homicide for
prostitutes, there is likely something about the nature of sex work itself that is uniquely
relevant to the established higher risk of homicide for female prostitutes.
Some might argue that prostitutes facilitate victimization by the very nature of their
work. Hickey (2006, p. 159) found that as many as 20% of serial murder victims since
1975 facilitated their own deaths “by placing themselves at risk.” Analyzing victim
lifestyle, type of employment, and location at the time of abduction or death, Hickey
(2006) observed prostitution as one of several factors indicative of victim-facilitated
homicide. Recent research on victims of domestic violence demonstrates that victim
behaviors such as previous failures to cooperate with police and prosecutors and infi-
delity are related to the propensity to blame victims for the crimes they endure (Taylor,
2009). Moreover, many serial murderers who targeted prostitutes did not kill all or
even most of the prostitutes with whom they had contact. In the case of serial murder,
court records and other accounts suggest that more subtle factors such as the offender’s
perception that the victim lied, cheated, insulted, or hurried them—not just the
nature of prostitution itself—may be at play (Kinnell, 2008; Rule, 2004; Selby &
Canter, 2009; State of Washington v. Gary Leon Ridgway, 2003).
Other research suggests that from the offender’s perspective and to some extent
public perception, a prostitute’s social status (or lack thereof) allows the offender to
downplay the death and dehumanize the victim (Fox & Levin, 1994). The concept of
the “less dead” (S. Egger, 2002)—marginal victim populations such as drug users,
prostitutes, migrant workers, and other transients—suggests that some victims matter
less than others. The idea that the disappearance and/or murder of some victims mat-
ters more than others was illustrated during the trial of serial killer Charles Jackson.
Jackson’s prosecutor, the Alameda County District attorney, specifically noted that “He
picked on people who meant something to someone” (McDonough, 2005, p. 1) implying,
intentionally or not, that some victims do not mean something to anyone. The victims
in this case were not prostitute victims. Serial killer Derrick Todd Lee, apprehended in
2003, was likely responsible for at least five female nonprostitute victims. In contrast to
several cases involving prostitute victims, a manhunt was already underway in Baton
Rouge when Lee killed his second victim. Interviews of law enforcement and journalists
offer insight into how the social status of victims chosen by Lee might have contributed
to public interest and quick investigative work. Statements referring to “another beau-
tiful, smart, educated, attractive girl with a promising future . . .” and “. . . they weren’t
expecting something like this to happen” imply that victim status is related to interest
in a case (Investigation Discovery, 2008). There is no scientific evidence that police
devote less time to the investigation of prostitute homicides. Case management differ-
ences are more likely a result of a lack of information about prostitute victims (e.g., no
missing persons report) which in and of itself may facilitate longer killing periods
and higher numbers of victims for offenders who target prostitutes and other transient
Prostitutes may be more vulnerable to serial killers as members of a population of
people referred to as the “missing missing”—missing persons who were never reported
as missing (Quinet, 2007). Because authorities are often unaware of crimes involving
the “missing missing,” investigations are delayed. Undercounting the “missing missing”
and other serial murder victim populations has likely contributed to underestimating
the annual number of serial murder victims in the United States by at least a factor of 2
and by as much as a factor of 10 (Quinet, 2007). Homelessness and the transient nature
of prostitutes and the lack of a stable social community, likely complicate investiga-
tion of prostitute homicides. A study of prostitutes in Colorado Springs found than 34%
of adult prostitutes had not lived in a household in the last 6 months, living instead in
homeless shelters, halfway houses, hotels, rooming houses, or on the street, with some
having been in prison or jail (Brewer et al., 2000). Recent research indicates that detec-
tion and investigation of prostitute homicides are further complicated by crime scene
behaviors which delay victim discovery and hamper forensic analysis—movement of
the body from the original crime scene, leaving victims outside and exposed to the
elements, and hiding victim bodies (Salfati et al., 2008).
In the United States, the Green River Killer case (Gary Leon Ridgway) resulted in
the highest number of convictions for a serial murder case—for 48 women, all of whom
were prostitutes. At sentencing, Ridgway stated,
I picked prostitutes as my victims because I hate most prostitutes and did not want
to pay them for sex. I also picked prostitutes as victims because they were easy to
pick up without being noticed. I knew they would not be reported missing.
I picked prostitutes because I thought I could kill as many of them as I wanted
without getting caught. (State of Washington v. Gary Leon Ridgway, 2003, p. 7)
For Ridgway, the selection of prostitutes as victims was a function of access and
opportunity, calculation of a longer active killing period (lower risk of detection) because
82 Homicide Studies 15(1)
victims would not be missed, and a hatred of prostitutes. Recent research suggests that
Ridgway’s reasoning was not unique. Salfati et al., (2008) documented several fac-
tors underlying the selection of prostitute homicide victims in the United Kingdom.
Availability; opportunity; expressive motivations (hatred of prostitutes and sexually
active women); lack of public interest in the welfare of prostitutes; the secretive, unpro-
tected, isolated, and solitary nature of prostitution work; the location of prostitution in
high crime areas; the unwillingness of prostitutes to talk to the police; and complex
forensic DNA sampling due to multiple client partners may all contribute to an increased
risk of homicide in this population.
To what extent do these occupational characteristics, all of which typify prostitution
in the United States (and abroad) as the current review has shown, inflate the proportion
of serial murder victims who are prostitutes and the proportion of serial murderers who
prey on prostitutes in the United States? Academic serial murder datasets focusing on
U.S. serial murder cases, summarized in Table 1, provide insight into the amount of
serial murder offenders and their victims in the United States. As noted previously, with
one exception (i.e., the work of S. Eggar and K. Egger, 2002 cited in Table 1), existing
datasets were not specifically created to permit estimation of the proportion of cases
with female prostitutes as victims. Moreover, all existing datasets vary in the time span
and region covered, types of cases included (solved vs. unsolved), the criteria consti-
tuting serial murder, the amount and nature of information collected, and the extent to
which they focus on victim typology. Consequently, it is not possible to rely on these
sources alone to understand the prevalence of female prostitutes as targets of serial
killers in the United States.
Clearly, as referenced above, much work has been done in the area of serial murder
and prostitution, including prostitute homicide, but to date, little work has focused exclu-
sively on analyzing the proportionate amount of serial murder risk for prostitutes, and
how this risk may have changed over time. To help clarify existing estimates of the pro-
portion of U.S. serial murder victims who were prostitutes, ranging from a low of 12.5%
of total victims to a high of 78% of all female victims, the current study uses primary
data collection to identify the proportion of U.S. serial murder cases since 1970 involv-
ing known female prostitute victims and whether this proportion has changed over
time. Victim gender alone and in relationship to prostitution status, the average num-
ber of victims and length of active periods in prostitute and nonprostitute cases also is
A serial murder database was compiled for this study. U.S. serial murder offenders
whose crimes were committed during the period 1970-2009 and details about their
crimes, including the number of serial murder cases, gender of victims, and other
victim characteristics were identified using all of the following methods. Once iden-
tified, all available information was entered into the database. The search process
1. Review of existing U.S. academic serial murder publications and presentations
(Aamodt et al., 2007, 2008; S. Egger, 2002, 2003; K. Egger, 2002; Hickey, 2006;
Fox & Levin, 1985, 2005; Frasier, 1996; Jenkins, 1989, 1990; Newton, 2006;
Rossmo, 1995), focusing on research that included quantitative information on
serial murder and/or specific U.S. case and victim details.
2. Internet searches of national media using multiple search engines and multiple
key words (e.g., serial killers, serial homicides, serial murders, serial murder-
ers, female serial killers, black serial killers, unsolved serial murders, medi-
cal murders, hospital serial killers, health care serial killer, prostitute murders,
prostitute homicides, victim names and offender names; see Brewer et al.,
2006, for an excellent search strategy of national media samples) were per-
formed and included searches of the World Wide Web using Google, Yahoo,
and Bing search engines, as well as LexisNexis and ProQuest, UPI, and online
archives of newspapers. Only sources available in the public domain were
used to establish case details. The search strategy mirrored that of other serial
murder research (Aamodt et al., 2007, 2008; S. Egger, 2002, 2003; Fox &
Levin, 2005; Hickey, 2006) that relied on national media searches. The present
research did not include interviews with offenders or access to a special exist-
ing database (e.g., Godwin, 2008; Rossmo, 1995).
3. Once a case was identified for possible inclusion (we originally began with
a working list of nearly 1,000 cases), a team of undergraduate and graduate
students searched for additional information (during a series of independent
research courses, 2004-2009) to see if the case met the inclusion criteria (three
or more homicides in three or more separate incidents). Cases were reviewed
by at least two students and final decisions and all final coding was done by
Serial murder offenders and the details of their crimes were considered for inclusion
in the database only if at least two references (e.g., court documents, biographical
books/“true crime” literature, newspaper and magazine articles including archives,
online inmate databases including state correctional department web sites and offender
registries) could be located.5 There are a number of serial murder blogs and serial murder
web sites and these sources were sometimes used to identify a possible case for inclu-
sion but the case was not included unless there were newspaper or magazine articles,
books, other academic references, or court documents to verify case details.6
1. Offenders were included (i.e., counted as a case) only if they had killed three
or more victims in three or more separate incidents—a case can be a single
offender, a couple, or multiple offenders. This definition, three or more vic-
tims, is used by Aamodt et al. (2007, 2008), Godwin (2008), Hickey (2006),
and Rossmo (1995). Egger (2002) defined serial killers as those who had
84 Homicide Studies 15(1)
killed two or more victims, Fox and Levin (2005) included only those offenders
who killed four or more victims.
2. Serial killers were excluded if their first known murder was committed before
January 1, 1970.
3. Murder cases attributed to serial killers were excluded if the offender had
been acquitted of all criminal charges (or if criminal charges had been dis-
missed or convictions overturned) and they had not been held civilly liable
for the victim’s death. The latter event, no criminal conviction but a finding
of civil liability for the deaths (e.g., a nurse who killed patients) qualified a
case for inclusion in the database.
4. Similar to other existing academic databases (e.g., Fox & Levin, 2005;
Missen, 2000) homicides committed as part of organized crime, or gang or
political movements were excluded.
For each case, the following data elements were compiled and recorded in the data-
base: year of the offender’s first and last known murders, location (states) in which the
offender killed, total number of known victims, number of victims the offender was
criminally convicted of murdering (or held civilly liable for), number of additional
suspected victims (uncharged cases), the types of victims murdered (e.g., elderly, col-
lege students, children, prostitutes, etc.), and victim gender (males only, females only,
both). Cases are counted in the decade they began (e.g., a case spanning 1974-1984 is
counted in the decade of the 1970s) There were no missing values for data presented in
the current analysis.7
The database covers 3,228 victims of 502 solved U.S. serial murder cases, 1970-2009.
The present analysis is case based and a case consists of all serial murders known to
have been committed by an individual offender or team of offenders. In some serial
murder cases, it is difficult to find reference to victim type for every one of the offender’s
victims. It is often known, however, that in a series of murders the majority of the known
victims were, for example, prostitutes, children, or hospital patients. Consequently, the
most reliable coding strategy was to record the primary victim type for each case, with
“primary” being defined as half or more of total victims. Thus, the primary victim type
for a case involving both female prostitute and nonfemale prostitute victims was
record as “prostitutes” if the majority of victims were, in fact, prostitutes. If a specific
case had five victims, three of whom were prostitutes, it was coded as a prostitute case.
While some cases that included mixed victim types included known nonprostitutes
(e.g., a female walking alone) and prostitutes, the vast majority of the cases coded as
having prostitute victims with some nonprostitute victims included drug addicts and
other transient victim categories as the nonprostitute victims (who may have been pros-
titutes but were not identified as such in media reports or referenced academic pub-
lications). Some cases coded as a prostitute case included known prostitutes and other
victims who were known to be drug-addicted or homeless and also likely to be prostitutes
but no media or scholarly reference to their status as a prostitute could be established
(so technically this is a mixed-victim case when in reality all victims were likely fad-
ing in and out of the prostitution lifestyle). In sum, the present coding strategy does not
overestimate the prevalence of prostitutes as serial murder victims. And, since some
cases did include a mix of mostly prostitute victims as well as drug-addicted, transient,
or homeless victims, the findings of the present research can be extended not just to
focus on the risk to prostitutes but also others who live and work in dangerous places,
live a street-based lifestyle that puts them in contact with strangers in high crime areas
and suffer the same vulnerabilities as prostitutes. As noted by Salfati (2009), street
prostitutes are vulnerable to victimization not just because they are prostitutes but
because of their vulnerable lifestyle, a lifestyle not necessarily unique to prostitutes.
While this case-based coding strategy maximized the accuracy and reliability of
victim types for cases, “prostitute victim” cases also could have included some, albeit
usually very few, nonprostitutes. Also, some cases coded as nonprostitute cases may
have included prostitutes (albeit relatively few). An unavoidable limitation of this and
all serial homicide datasets is that what is not known about victims cannot be known.
For example, it might easily not be known if a hitchhiker, runaway, a person with a his-
tory of drug offenses, a college student, or person from any social group also worked as
a prostitute. Some media case coverage would refer to victims as prostitutes only if they
had a previous arrest history of prostitution or were known prostitutes to persons inter-
viewed in the case. So, although some cases include mixed-victim types, in many of
those cases, all of the victims were in fact working as prostitutes. We know from other
research on prostitutes that it is the novice prostitute, new to an area, having worked
only days or weeks as a prostitute (with no criminal history) that is particularly vulner-
able to dangerous clients (Kinnell, 2008). Future research could assess the difference,
if any, in the nature of cases that include only prostitute victims and those that include
prostitute victims as well as drug-addicted and homeless victims. One could speculate
that the hunting grounds for victims, the ruses used to lure victims, the number of victims
per case, and the length of active killing periods may be similar for prostitute–only and
mixed-victim cases that include victims living similar lifestyles that bring a transient
victim pool into contact with strangers in dangerous areas.
The current study focuses only on solved cases in which the murder series began prior
to 2010. Previous work suggests that on average, serial killers may be active as long as
9 years before being detected (Hickey, 2006). Consequently, the number of solved serial
murder cases since 2000 will likely increase as additional cases are discovered over time.
As possible serial murder cases were researched, some cases had extensive coverage as
unsolved cases, sometimes for many years. Before accepting that a case was truly
unsolved, an extensive online search was made to uncover information about possible
later arrests, convictions, exceptional clearances, DNA evidence, and/or law enforce-
ment opinion that effectively solved the case. Some cases originally declared as unsolved
in a number of early media and academic sources, for many years in some instances,
were eventually solved and all or at least part of the series of murders was able to be
linked to an offender and is included in the database.
86 Homicide Studies 15(1)
The analyses below describes trends in the number of solved serial murder cases and
victims by decade, the gender distribution of victims of serial murder over time, the
victim gender in prostitute and nonprostitute cases, and trends in the number of pros-
titute and nonprostitute cases, victim counts, and length of active killing periods by
Overall Trends by Decade
Examination of the proportion of serial murder cases by decade shown in Table 2,
suggests a precipitous drop in the number of cases and victims from the 1980s to the
1990s, similar to observations made by Hickey (2006) and Fox and Levin (2005).
Thirty-four percent of all cases in the dataset began during the decade 1970-1979 and
37% began 1980-1989 compared to only 24% having begun sometime during 1990-
1999. As the decade 2000-2009 drew to a close, 28 solved serial murder cases (and an
additional 10 unsolved active cases, not shown) have been detected as having begun
since 2000. If this 2000-2009 number of cases were to remain constant, only 5% of
all cases in the cumulative dataset (28 out of 502) will have occurred during 2000-
2009, reflecting a dramatic reduction in detected cases of serial murder by decade.
If the 10 additional unsolved cases were all eventually solved and added to the count,
only 7% of serial murder cases will have occurred in a decade representing 25% of
the time period of study.8 Hickey (2006, p. 137) also noted the declining frequency of
serial killers between 2000 and 2004. It appears that as overall homicide rates across
the United States have declined to levels not seen since the mid-1960s, the phenom-
enon of serial murder has declined as well. During 1970-2009, 71% of known solved
serial murder cases occurred in the 1970s and 1980s. Assuming that media coverage
of serial murder cases has increased due to public interest and the number of media
outlets, the 1990-2009 decline is even more extraordinary as more recent cases were
more likely to receive more extensive media coverage. However, even if the number
of known cases for 2000-2009 doubled or tripled (as more previously unknown cases
were discovered), we would still be far below the number of cases seen in the previous
Table 2. Solved Serial Murder Cases and Victims by Decade
Decade Cases % of total, 1970-2009 Victims % of total, 1970-2009
1970-1979 168 34 1,277 40
1980-1989 188 37 1,144 35
1990-1999 118 24 645 20
2000-2009 28 5 162 5
Total 502 100 3,228 100
decades. The number of serial murder victims during 2000-2009 is 13% of the peak
number of victims seen in the 1970s.
Serial Murder Victim Gender
Table 3 presents the number of cases categorized by the gender of serial murder victims,
overall and by decade. Historically, victim gender has been examined in two different
ways: (a) counts of known victims by gender, and (b) counts of the number of cases
resulting in female and male victims (i.e., counts of the number of offenders who
killed females, males, or both). Using the former method, three studies (S. Egger,
2003; Godwin, 2008; Kraemer et al., 2004) found that 65% to 67% of serial homi-
cide victims were female, and Rossmo (1995) observed that 72.5% of victims were
female.9 Using the latter, more precise method, Hickey (2006) observed that 39% of
Table 3. Serial Murder Victim Gender, Overall and by Decade
n of cases Percentage of cases (%)
Cases with female victims only 261 52
Cases with male victims only 76 15
Cases with both female and male victims 165 33
Total 502 100
Cases with female victims only 83 49
Cases with male victims only 25 15
Cases with both female and male victims 60 36
Total 168 100
Cases with female victims only 97 52
Cases with male victims only 31 16
Cases with both female and male victims 60 32
Total 188 100
Cases with female victims only 65 55
Cases with male victims only 16 14
Cases with both female and male victims 37 31
Total 118 100
Cases with female victims only 16 57
Cases with male victims only 4 14
Cases with both female and male victims 8 29
Total 28 100
88 Homicide Studies 15(1)
serial killers had female victims only, 21% had male victims only, and 40% had both
female and male victims.
Using the latter method, these data indicate that of the 502 solved serial murder
cases in the current study for the 1970-2009 period, 52% of offenders killed females
only and 15% killed males only (Table 3). Thirty-three percent of serial murderers
killed both females and males. Thus the proportion of cases in the current study result-
ing in female victims (either entirely or in part) is 85%, similar to the proportion of
cases including female victims (79%) observed by Hickey (2006).
Taken together, these estimates demonstrate that, unlike nonserial homicides in
which males are more likely to be victimized, for serial homicides female victim only
cases are approximately 3.5 times more likely than male victim only cases (52% vs.
15% in the current study). Using a case-based analysis, the best estimate of the propor-
tion of offenders who exclusively kill females is 39% to 52% (Hickey’s 2006 findings
and the present findings), while 79% to 85% of serial murder offenders kill at least one
female during their active killing periods.
Analysis of new data presented here shows an increase over time for the category
of female victims only (Table 3). The percentage of serial murder cases with female
victims only increased every decade, from 49% to 57% over the entire time period.
The proportions of cases resulting in female victims either entirely or in part (includ-
ing offenders who killed both males and females) by decade are 85%, 84%, 84%, and
Serial Murder Victim Gender
in Prostitute and Nonprostitute Cases
A specific objective of this study was to clarify existing estimates of the proportion of
serial murder cases with prostitute victims, separately by victim gender. Counting vic-
tims, Rossmo (1995) observed that 22.5% of all victims (both female and male) were
engaged in prostitution when they were murdered, whereas S. Egger (2003, p. 49)
reported that “nearly 78 percent of female victims of serial murderers are prostitutes.”10
Case counts (as opposed to victim counts) variously suggest that 12.5% (Aamodt et al.,
2008; M. Aamodt, personal communication, July 13, 2009); Fox & Levin, 2005) and
21% (Godwin, 2008) of serial murder offenders kill prostitutes. The gender of prostitute
victims in these observations is not known and the cases are not necessarily exclusively
With the exception of S. Egger’s (2003, p. 49) observation that “nearly 78 percent of
female victims of serial murderers are prostitutes,” existing estimates of prostitutes as
targets of serial killers are similar, ranging from 12.5% to 22.5% (Aamodt et al., 2008
and M. Aamodt, personal communication July 13, 2009; Fox & Levin, 2005; Godwin,
2008; Hickey, 2006). Consistent with these studies, 22% (110 of 502) of all cases in
the current study involved prostitute (male or female) victims (see Table 4). Overall,
1970-2009, the proportion of cases involving only female prostitute victims was 17%
(83 of 502 cases). When cases did involve prostitute victims, however, they typically
involved female, not male, prostitutes (75% or 83 of 110 prostitute cases were female
prostitutes only). As noted by Brewer et al. (2006), it is difficult to disentangle com-
mercial and noncommercial homosexual encounters (including those that may result
in a homicide). The work of Drake (2003, 2004) has noted not only the paucity of
research on homosexual homicides but also the difficulty in recognizing a homicide as
a gay homicide. During data collection for the present study, it was common that in
cases of male victims of male serial murder offenders, victims were referred to in media
accounts as “hustlers” rather than prostitutes. A close read of such cases sometimes
resulted in a designation of victims as prostitutes but the present research, as well as
other research, may underestimate the number of male serial murder victims who were
The extent to which the risk of homicide may vary for female and male prostitutes
is unclear as nearly all existing studies focus on female prostitutes. When male prosti-
tutes are studied, the work typically focuses on men—often referred to as hustlers or
transients—whose clients are men. Even when picked up off the streets or in a bar known
for gay prostitute trafficking, clear designation of a male homicide victim as a prostitute
is rare or nonexistent (Drake, 2003, 2004). One recent exception to the research focus on
female prostitutes is Connell’s (2009) work on the personal safety and violence experi-
ences of 27 male prostitutes in Scotland. The Connell work illustrated that male prosti-
tutes, like female prostitutes, suffer verbal, physical, and sexual attacks; take precautionary
measures when possible; and do not report their victimization experiences to the police
Looking at the entire time series, 1970-2009, the present research finds that of cases
with female victims only (n = 261), 32% (n = 83) involved prostitute victims. This
estimate is in contrast to Egger (2003, p. 49), who suggested that only 22% of female
serial murder victims were not prostitutes, whereas in the present study, the vast major-
ity (68%) of cases involving female victims only for the entire time series, were not
female prostitutes (also shown in Table 4). Only 8% of cases, 1970-2009, involving
both female and male victims included prostitute victims. Other researchers similarly
grouped several decades when describing the likelihood that victims were prostitutes.
However, Table 4 also reveals that the proportion of cases involving prostitute victims
has dramatically increased by decade, despite the decline in serial murder cases overall
between the 1980s and 2000s. The proportion of cases in which prostitutes (both female
and male) were victimized during 1970-1979 was 13%, increasing in each of the sub-
sequent decades (21% during 1980-1989, 31% during 1990-1999, and though based on
a much smaller number of cases, 43% for 2000-2009). As previously noted, we can
be much less certain of the prostitution status of male victims. Thus, analyzing female
victim only cases finds the proportions of cases involving female prostitute victims
was 16% during the 1970s, 30% during the 1980s, 46% during the 1990s, and 69%
from 2000 to 2009. As the number of cases of serial murder declined from the 1980s
to the 2000s, the likelihood that the victim was a prostitute, particularly a female pros-
titute, increased. Although Egger’s (2003) estimate that 78% of female serial murder
90 Homicide Studies 15(1)
victims are prostitutes seemed high compared to all other estimates, the present analysis
estimates are generally comparable, but show a somewhat lower proportion of female
serial murder victims who are prostitutes, for the 2000-2009 period (69%). Early esti-
mates (using cases in the 1970s and 1980s) of the proportion of serial murder victims
who were prostitutes or estimates that combined data from several decades have failed
to uncover a trend detectable only through disaggregation. As noted previously, there
are an additional 10 unsolved serial murder cases under investigation for 2000-2009
and nine of those cases involve prostitute victims, seven of the nine with female only
Table 4. Serial Murder Victim Gender in Prostitute and Nonprostitute Cases,
Overall and by Decade
prostitutes Nonprostitutes Total
n of cases Row % n of cases Row% n of cases
Cases with female victims only 83 32% 178 68% 261
Cases with male victims only 13 17% 63 83% 76
Cases with both female and male victims 14 8% 151 92% 165
Total 110 22% 392 78% 502
Cases with female victims only 13 16% 70 84% 83
Cases with male victims only 4 16% 21 84% 25
Cases with both female and male victims 4 7% 56 93% 60
Total 21 13% 147 87% 168
Cases with female victims only 29 30% 68 70% 97
Cases with male victims only 4 13% 27 87% 31
Cases with both female and male victims 7 12% 53 88% 60
Total 40 21% 148 79% 188
Cases with female victims only 30 46% 35 54% 65
Cases with male victims only 4 25% 12 75% 16
Cases with both female and male victims 3 8% 34 92% 37
Total 36 31% 81 69% 118
Cases with female victims only 11 69% 5 31% 16
Cases with male victims only 1 25% 3 75% 4
Cases with both 0 0% 8 100% 8
Total 12 43% 16 57% 28
Victim Counts and Active Periods
Table 5 presents analysis of average victim counts across the decades and average
number of years active for all cases, prostitute cases, and nonprostitute cases. Hickey
(2006) reported a range of 7 to 10 victims per serial murder cases for offenders active
1975-2004. The present analysis finds a lower average number of victims, ranging
from a high of 7.6 in the 1970s to 5.5 in the 1990s and 5.8 by 2000-2009. The average
number of victims per case in each decade is higher for prostitute cases than nonprostitute
cases. Those who kill prostitutes kill more victims than those who kill nonprostitutes,
and these differences were larger in earlier decades. More recently, 2000-2009, nonpros-
titute killers average 5.3 victims per case and prostitute killers average 6.4.
Godwin’s (2008) analysis of serial murder cases from 1950 to 1995 found killers to
be active for an average of 7.5 years. The present research, disaggregating by decade,
finds that serial killers remained active an average of 9.3 years in the 1970s, declining
almost by half to 5.1 by the 1980s, 3.2 by the 1990s, and 2.2 years by 2000-2009. Hickey’s
(2006) analysis of serial murder cases from 1800 to 2004 found that serial killers remained
active approximately 9 years reflects early decade trends and the present analysis sug-
gests a substantial decline in the length of time a serial killer remains active. Hickey’s
findings appear to have been dominated by the large number of cases in the 1970s and
1980s and there appears to have been a decline in more recent decades in the average
Table 5. Total Prostitute and Nonprostitute Victim Counts, and Active Periods
Decade Cases Victims
Average number of
victims per case
of years per case
Overall: case and victim count, with active period years
1970-1979 168 1,277 7.6 1,555 9.3
1980-1989 188 1,144 6.1 963 5.1
1990-1999 118 645 5.5 377 3.2
2000-2009 28 162 5.8 61 2.2
Total 502 3,228 6.4 2,956 5.9
Prostitute: case and victim count, with active period years
1970-1979 21 254 12.1 215 10.2
1980-1989 40 313 7.8 256 6.4
1990-1999 37 241 6.5 150 4.1
2000-2009 12 77 6.4 36 3
Total 110 885 8 657 6
Nonprostitute: case and victim count, with active period years
1970-1979 147 1,023 7 1,340 9.1
1980-1989 148 831 5.6 707 4.8
1990-1999 81 404 5 227 2.8
2000-2009 16 85 5.3 25 1.6
Total 392 2,343 6 2,299 5.9
92 Homicide Studies 15(1)
length of time a serial killer remains active. Table 5 also shows that, for each decade,
the average length of time that offenders were active was longer for cases involving
prostitute victims than nonprostitute victims.11
If serial killers are now averaging 1.6 to 2.8 (1990-2009) years active, the present
database for 2000-2009 may be lacking fewer undetected cases than suggested by
Hickey’s (2006) finding of an active period of 9 years for serial murder cases.
Serial murder in the United States appears to be declining, although as illustrated
in Table 5, the number of prostitute victims killed declined by nearly 75% from the
1980s to 2000-2009 (313 vs. 77 victims), whereas the number of nonprostitutes killed
from the 1980s to 2000-2009 declined by 90% (831 vs. 85 victims). During the 1980s,
when the number of known serial murder cases was peaking, approximately 27% of
serial murder victims were prostitutes, however, during the most recent decade, approx-
imately 48% of victims were prostitutes.12 The number of serial murder victims and
prostitute victims has declined since the 1980s, but, given a serial murder case, the
likelihood that the victim’s are female prostitutes has increased.
The key aims of this study are to establish a count of the number of cases of U.S. serial
murder, 1970-2009, and assess changes in the number of serial murder cases and the
gender distribution of victims over time. In addition, the present study examines the
overall and disaggregated time trends for a specific type of serial murder victim, pros-
titutes, and the average victim count and length of killing series for prostitute and non-
The present findings have illustrated the rise and precipitous decline in the number
of serial murder cases since 1970. A limitation of this research, as well as other serial
murder research, is suggested by recent research, finding that all along, including now,
we have overlooked some serial murder victims from several victim pools (Quinet,
2007). Some proportion of unidentified dead, missing persons, missing persons who
were never reported as missing, and misclassified deaths (e.g., medical murders) if they
were known, would add to our annual serial murder counts (Quinet, 2007). Also, the
present work is primarily case based and includes some cases of mixed-victim type that
were coded as prostitute cases because half or more of the victims were known prosti-
tutes. If there is something uniquely different about the type of offender who kills pri-
marily prostitutes but also drug addicts, runaways, homeless persons, or an occasional
woman alone, versus the offender who only kills prostitutes, then we need more
research. Finding that a prostitute killer had some nonprostitute victims, or that a hos-
pital patient killer (e.g., Donald Harvey) also killed neighbors and acquaintances
should not negate the primary victim selection and the primary places these predators
hunt. We can still focus our limited resources appropriately. To prevent the serial killer
who targets mostly prostitute victims from accumulating high victim counts we can
most efficiently focus our prevention resources on prostitutes, and many of these same
resources, (e.g., increased law enforcement presence, social services) may also help to
prevent the drug addicted and homeless from becoming serial murder victims. Likewise,
the serial killer who operates primarily in medical settings can be most effectively
prevented by focusing our resources in this setting (e.g., death surveillance systems).
Mixed-victim categories do not negate that in most cases, a majority of victims were
of a similar type (e.g., prostitutes, homeless) and effective intervention and prevention
strategies to prevent most of that killer’s murders can be designed. The serial killer who
targets women alone in their homes—whether young women, two women, elderly women,
a mixed-victim age category—can potentially be deterred by the same strategies—
targeting the security of the home.
As noted previously, male prostitute cases are less definitive in media coverage as
male prostitutes are sometimes referred to as drifters or hustlers rather than prostitutes.
Thus the present research likely underestimates the number of male prostitutes in cases
with male offenders and male victims.
The current study confirmed, similar to the findings of others, that in contrast to
single homicides, females are more likely than males to be targeted by serial homicide
offenders. From 1970 to 2009, 52% of offenders targeted female victims only, 15%
targeted male victims only, and 33% targeted both females and males. The proportion
of offenders choosing female victims only increased over time but the proportion that
killed both females and males declined somewhat (from 33% of cases in the 1970s to
29% of cases during 2000-2009). The finding that the proportion of cases involving
female victims only has increased, likely ties to the increase in the proportion of cases
in which the victims were prostitutes.
Overall, 32% of cases involving female victims only were prostitute cases. However,
disaggregation by decade showed that the proportion of cases in which only female
prostitutes were victimized increased from a low of 16% between 1970 and 1979, to 30%
between 1980 and 1989, to 46% between 1990 and 1999, and 69% between 2000 and
2009. Thus, despite an observed dramatic decline in the total number of serial murder
cases from the 1980s to the 1990s, the likelihood that the victim was a female prosti-
Given divergent estimates in the existing literature, the purpose of this analysis is to
clarify the risk of serial homicide for female prostitutes so that prevention and investi-
gation efforts designed to curtail high serial murder victim counts can be appropriately
channeled. The observation that from 1970 to 2009, 32% of all female victims of serial
murder were known prostitutes suggests that female prostitutes are in fact a target for
serial murder offenders in the United States, and the present analysis additionally indi-
cates that this targeting has been increasing over time. It is possible, but not definitively
known, that the observed increase in overall prostitute homicides reflects burgeoning
high risk behaviors among drug-addicted prostitutes during the crack cocaine epi-
demic of the 1980s and 1990s (Brewer et al., 2006). As U.S. homicide rates began to
decline in the 1990s, the number of serial murder cases also declined and thus, serial
murder as a form of homicide appears to increase and decrease with more general
homicide trends. But, whatever factors may explain a decline in serial murder victim-
ization and overall homicide victimization for the general population, these factors are
94 Homicide Studies 15(1)
not functioning in the same way for prostitutes, as their proportion of the total serial
murder victim pool increased over time (although the numbers have declined for pros-
titutes as well). As the U.S. economy worsens, more persons are homeless and lacking
legal employment opportunities. The number of persons living vulnerable lifestyles
may be increasing and this may concentrate serial murder victimization in specific vic-
tims who are more accessible (e.g., prostitutes, drug-addicted persons, homeless, run-
aways). Other serial murder research has focused on vulnerability and opportunity as
key victim selection variables for many serial murder offenders.
Recent research has begun to fill the void regarding the experiences of violence and
homicide for prostitutes and highlights the attention paid to domestic violence strategies,
but not for prostitute violence reduction (Canter, Ioannou, & Youngs, 2009; Holden,
Gonza, & Richards, 2009). Also, strategies of controlling or curbing street prostitution
(rather than focusing on preventing homicides against prostitutes) may inadvertently
contribute to the prostitute homicide problem by reducing the visibility of prostitute
transactions. Public order and law enforcement strategies may negatively affect safety
by geographically and temporally displacing prostitutes into less safe areas and more
hurried transactions with less attention to potential risk factors (Canter et al., 2009;
Hubbard & Scoular, 2009; Penfold, Hunter, Campbell, & Barham, 2004). Ironically,
such strategies also may increase the number of prostitute transactions to offset fines and
court costs associated with enhanced enforcement (Penfold et al., 2004).
Strategies which help prostitutes out of prostitution, encourage reporting of vic-
timization to the police, and enable prostitutes to avoid dangerous clients and situa-
tions may help prevent prostitute homicides. Recent work suggests that multiagency
efforts encouraging prostitutes to report violent incidents to outreach workers may
increase reported violence and convictions against violent clients (Penfold et al., 2004).
Qualitative and quantitative analysis of prostitute behavior found a number of self-
protective measures such as “. . . relying on intuition in determining the safety of a
client, meeting clients in designated areas, refusing to travel more than a few blocks
with clients, and making exchanges in visible areas (e.g., near street lights)” (Dalla,
Xia, & Kennedy, 2003, p. 1381). Prostitutes also refused clients driving vehicles asso-
ciated with dangerous clients, and some prostitutes reported that they carried a weapon
(Dalla et al., 2003).
Dalla et al. (2003) suggest that an effective intervention strategy will include a support
system for prostitutes with sponsors and mentors, and emotional and practical support,
rather than punitive measures alone (see also Canter et al., 2009 and Kinnell, 2008). Such
strategies should consider research that finds Black and White prostitutes may work at
different times (day vs. evening) and at different places (part of the general citizen
population vs. in separate areas; Riccio, 1992). Prostitutes are likely to live near where
they work (Riccio, 1992). Thus support resources may best be placed in areas where
Prostitute homicides present unique challenges for law enforcement investigation.
Salfati et al. (2008) observed that 46% of prostitute homicides were unsolved. Brewer
et al. (2006) found that the time to arrest for single prostitute homicides was longer
than 1 year for 41% of all cases and longer than 5 years for 17% of cases. The present
research suggests a decline over time in both the average number of victims per serial
murder case, overall and for prostitute and nonprostitute cases, and a decline in the
amount of time offenders are active for both prostitute and nonprostitute cases. We
should not overlook the likely impact of improved police investigative strategies in
explaining these trends and future research should assess the proportion of unsolved
serial murder cases that include prostitute victims.
Previous convictions for violent and sexual offenses are higher among clients who
murder prostitutes compared to a general population of prostitute clients (Brewer et al.,
2006; Salfati et al., 2008). Recently, Dudek, Brewer, Nezu, and Nezu (2009) found very
little difference in the demographic and criminal history variables of persons who killed
a single prostitute and those who were offenders in serial prostitute killing. Serial per-
petrators were slightly more likely to have a criminal history including sex offenses,
but given the vast similarities between those who kill one prostitute and those who kill
more than one (particularly since 20% of the single killers had nonfatal attack histories
against other prostitutes) nonpunitive law enforcement facilitation of assault reporting
by prostitutes may be an effective prostitute homicide prevention strategy. Circulating
descriptions of potentially dangerous clients based on law enforcement knowledge of
prostitute assaults and a history of violence among known clients also may be an effec-
tive deterrent. Kinnell (2008) describes the “Ugly Mug” outreach strategy of circulating
information to prostitutes, including photos and other information, about violent inci-
dents and violent individuals (as opposed to only those individuals and incidents known
to police). Brewer et al. (2006) recommended surveillance of areas where prostitutes
work and the collection of DNA evidence from arrested prostitutes and their clients.13
Such efforts might deter prostitution homicides, improve identification of prostitute
homicide victims, and lead to faster apprehension of their killers. Because 55% to
85% of arrested clients reside in the county of their arrest, maintaining a database of
known clients could be a useful tool for police investigations (Brewer, Roberts, Muth,
& Potterat, 2008).
Prostitutes lead transient lifestyles and are more likely to be among those who
were never reported as missing when they are in fact missing (Quinet, 2007). Linking
unsolved serial homicide cases with missing persons and the unidentified dead cases
presents an additional challenge for investigators (Kiger, 1990; Quinet, 2007). The
relatively new, publically accessible National Missing and Unidentified Persons
System (www.namus.gov) should help bring closure to unsolved serial murder cases
involving missing persons and unidentified dead. As S. Egger (1990) has noted,
increases in communication within and between police agencies is necessary to reduce
“linkage blindness,” thus shortening the active killing period of undetected, some-
times nomadic, killers. The present findings of reduced active killing periods suggest
we have made progress since the 1970s.
Historically, there is evidence that some detection and deterrence strategies have
protected certain groups of people from certain types of serial killers, such as those
specializing in insurance fraud (Jenkins, 1988). It also is true, however, that hardening
96 Homicide Studies 15(1)
one target may soften another, simply displacing the victim target. Vulnerable popula-
tions such as Jenkins’ “rootless in the 21st century” (1989) and S. Egger’s “less dead”
(1990) will continue to include the elderly, runaways, medical patients, prostitutes, an
increasing population of homeless persons, and a vulnerable population of illegal
immigrants. It will be important to continue to build knowledge of who falls victim to
this crime and why, if we are to appropriately spend our limited resources for serial
homicide prevention and investigation.
The author thanks Mary Ziemba-Davis, Samuel Nunn, Janet Lauritsen, Michael Aamodt,
Devon Brewer, Jamie Fox, Jack Levin, and anonymous reviewers for their comments on this
article and Tami Barreto and the Indiana University Public Policy Institute, Center for Criminal
Justice Research for editorial assistance.
A preliminary version of this article was presented at the American Society of Criminology
annual meeting St. Louis, Missouri, November 2008.
Declaration of Conflicting Interests
The author declared no potential conflicts of interests with respect to the authorship and/or
publication of this article.
The author received no financial support for the research and/or authorship of this article.
1. See Fox & Levin (2005) Figure 3.1, Table 3.1, and Table 3.2.
2. Personal communication from Aamodt included information on the exact number of pros-
titute cases in his database (email@example.com and http://maamodt.asp.radford.edu/
3. Six serial murderers in the database also were active outside of the United States, sometimes
due to military duty or employment (Canada, Mexico, Thailand, Israel, and/or Japan). Where
possible, only the U.S. victims were counted for these offenders.
4. Special thanks to students who searched for and coded (and re-coded!) serial murder cases:
Regina Pessagno, Alexandra Briggs, Jennifer Higgins, Konrad Haight, Garrett Mason,
Heather Braun, Samantha Shearon, and Hayley Roach. Special thanks to Jovita Williams
for bibliography assistance. Bibliography of sources used for case information available on
request to firstname.lastname@example.org.
5. The present search strategy for verifying case information is similar to that done by others
(Brewer et al, 2006 for prostitute homicides, Missen, 2000, as described in Canter & Wentink,
2004 for serial murder cases, Dudek et al., 2009, for single and serial murder cases involving
6. A bibliography of citations for each of the 502 serial murder cases included in the database
is available from the author by request. This is a large document, in excess of 150 single-
spaced pages, and includes at least two, but typically many more citations for each serial
murder case, allowing for independent corroboration of case details.
7. Other variables (e.g., offender race, method—gun, stabbing, asphyxiation, poison), offender
occupation, female offenders, medical murders) have also been coded but are either incom-
plete or outside the scope of the present research.
8. Of the 10 unsolved serial murder cases, 2000-2009, 9 of the 10 cases involve prostitute
victims. Although the present analysis only includes solved cases, as these unsolved cases
are solved, an even greater proportion of serial murder cases during 2000-2009 involved
9. Fox and Levin (2005) did not report the total number of serial homicide victims who are
female but noted that the proportion is greater than 38%.
10. This finding is cited in S. Egger (2003, p.49) and reported in the book, The Killers Among
Us by S. Egger (2002, p. 89) in a chapter written by K. Egger and the finding is attributed
data collected by K. Egger, 2000, but the reference section of The Killers Among Us does
not include a reference for K. Egger, 2000, but rather only K. Egger, 1999, which is cited as
an unpublished preliminary database of serial killers from 1900 to 1999. Later in the same
chapter by K. Egger this finding is conditioned by the statement “as much as 78 percent in
some time periods” (p. 91) but the relevant time period is not stated.
11. Although the average period active for each decade is lower for cases involving nonprostitute
victims, the averages across all four decades were similar for cases involving prostitute and
nonprostitute victims (i.e., 5.9 and 6.0, respectively). This reflects the fact that the distribu-
tion of cases is not the same across decades. Seventy percent of cases involving prostitute
victims occurred during the 1980s and 1990s, while most of the cases involving nonprostitute
victims (76%) occurred during the 1970s and the 1980s, and during the 1970s the average
length of activity was greater for both groups of victims.
12. Prostitutes as 27% of serial murder victims during the 1980s are calculated by dividing the
number of victims in prostitute cases (313) by the total number of victims (1,144) in pros-
titute cases (313) and nonprostitute cases (831). Prostitutes as 48% of serial murder victims
during 2000-2009 are calculated by dividing the number of victims in prostitute cases (77)
by the total number of victims (162) in prostitute cases (77) and nonprostitute cases (85).
Victim counts should be used as estimates of trends rather than exact estimates as some
prostitute cases contained some, albeit few, potential nonprostitutes and some nonprostitute
cases contained some prostitutes. Cases were coded as prostitute if half or more of victims
13. Several serial murder cases involve prostitute victims and truck driver offenders (Jesperson,
Ford, Fautenberry, the Las Vegas unsolved prostitute case, Rhoades, Williams, and Cumberland).
Surveillance at truck stops and other high-traffic prostitution areas may reduce the attrac-
tiveness of these hunting grounds. Recent media coverage of the FBI analysis of 500 murder
victims found near highways also suggested that many of the suspects in unsolved serial
murder cases may be long-haul truck drivers (Todd, 2009).
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Kenna Quinet is an associate professor of criminal justice, law, and public safety in the School of
Public and Environmental Affairs (SPEA) at Indiana University Purdue University Indianapolis
(IUPUI) and faculty fellow, Indiana Public Policy Institute, Center for Criminal Justice Research.
Her recent research focuses on homicide, missing persons, unidentified dead, and unclaimed dead.