Date of Award

Spring 6-2022

Document Type


Degree Name

Master of Arts (MA)


Forensic Psychology



First Advisor or Mentor

Gabrielle Salfati

Second Reader

Diana Falkenbach

Third Advisor

Philip Yanos


The literature suggests that offenders with prior criminal experience are likely to exhibit criminal expertise in future crimes to avoid detection, including planning behaviors and forensic awareness strategies. Many studies have found that the majority of serial and single homicide offenders already have criminal records before they commit their first homicides, yet no studies to-date have explicitly analyzed the relationship between their criminal careers and their use of criminal expertise. Therefore, the current study aimed to examine the relationship between 27 serial and 191 single homicide offenders’ criminal careers and the criminal expertise employed in their first homicides to differentiate homicide offenders with varying criminal career backgrounds and ultimately aid offender profiling efforts. First, the study established serial and single homicide offenders’ criminal career specializations using the expressive and instrumental framework, and subsequently differentiated them by their dominant criminal career groups (expressive specialist/ instrumental specialist/ generalist/ no criminal history). Next, the study sought to differentiate their criminal expertise actions by instrumental subgroups of control (control over the victim/ the outcome). Lastly, the study linked serial and single homicide offenders’ dominant criminal career groups to their dominant criminal expertise action groups. Multidimensional analyses followed by chi-square tests indicated that serial and single homicide offenders’ use of criminal expertise was the same across criminal career backgrounds, with the exception of single homicide offenders expressive specialists who were more likely to control the outcome of their first homicide. Implications of the results and future objectives for additional research are discussed.



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