The crime scene examination is conducted to assist with investigating a criminal incident and to identify the perpetrator(s) involved. Over the last few years, the field of forensics has made dramatic scientific advancements in DNA methodologies, analyses of methods of evidence, and the complexity of related databases. It has generally been proposed that the most dependable method for distinguishing crimes carried out by a specific offender is by comprehensively collecting and analyzing physical evidence at the crime scene (Grubin, Kelly & Brunsdon, 2001). One rather effective option has been DNA profiling. This is accomplished by carefully recording the conditions at a crime location and identifying all pertinent physical evidence. Once completed, DNA samples can be collected and subsequently analyzed in an approved crime lab. It is obvious that the capacity to uncover and appropriately gather physical evidence is vital to solving and investigating violent and serious crimes. On the other hand, in many criminal incidents, little or no physical evidence exists or is often not collected. More importantly, DNA profiling is both time-consuming and costly (Davies, 1991).
Physical evidence, such as DNA, can be utilized to correlate a crime with an unknown suspect, however in various crimes, there may not be any or sufficient physical evidence to identify the offender (Davies, 1991). It is in such circumstances that case linkage can be used in an effort to solve the crime. Case linkage is a mechanism that intends to distinguish crimes that have likely been committed by a particular suspect due to behavioral similarities across a number of crimes (Woodhams & Bull & Hollin, 2007). One important factor involves examing the apparent or potential relationship between the offender and the victim. This complex process involves victimology, the analysis of characteristics of the offender, the identification of the modus operandus of the offender, and the acknowledgment of signature behaviors between each of the cases under review. The purpose of criminal profiling is “to link crimes based on the behaviors that offenders engage in while committing their offenses” (Douglas & Burgess, 1986).
The process of case linkage includes a number of important stages. The first step involves concentrating on one specific offence exhaustively to comprehend the offender’s physical and verbal conduct. The basis of this analysis typically relies on the victim’s account of the crime. Next the analyst would attempt to identify and specify the pertinent behaviors in one incident in order to match it to other available crime reports (Grubin et al., 2001). There has been some discussion concerning whether particular behaviors which contribute to a crime’s ‘modus operandus,’ which are clearly related to the offender’s attempt to commit an offense effectively, ought to be utilized in the evaluation to connect crimes (Douglas & Munn, 1992), since modus operandus is a learned behavior and suitable to change. Some researchers do caution about the use of that for linking crimes. On the other hand, some new studies have shown that the modus operandus can be utilized effectively to identify a crime pattern and connect a series of criminal events (Bateman & Salfati, 2007). After a modus operandus and distinct attributes to one or more criminal incidents have been identified, it is critical that analysts compare those particular behaviors in one crime with other criminal events. Most importantly, they need to understand and note any similarities and differences involving each criminal incident. In this step, the analyst must consider the antecedents for each behavior, because the context wherein behavior happens is significant. Hazelwood and Warren (2003) make the point that “the analyst must consider the frequency with which the combination of behaviors in the offense occurs in its population of crimes.” It is these ‘signature behaviours’ that may reveal the psychological background of an offender (Keppel & Walter, 1999). In many cases, motivation and sexual fantasy play a dynamic role in shaping an offender’s character, attitude and outlook on life (Schlesinger, 1999). These are considered to be emblematic and extremely individual to each perpetrator.
It is important to acknowledge that many studies highlight only specific crimes types, mainly homicide and sexual assaults, and there is presently little research that glances at whether the way toward connecting criminal events for one crime type might be successfully transferred to linking crimes of other types. All in all, it is important to understand the decisions made by law enforcement personnel concerning what enhances analytical precision and to comprehend whether choices that increase investigative success are improved by conducting a thorough evaluation of the evidence, crime patterns and matching that information to potential criminal suspects.
Given that crime linkage is broadly utilized throughout the world,[1] there is clearly a need for more extensive research. For specific case linkage evidence to be acknowledged by criminal and civil courts, it is significantly critical that this option undergo logical examination, consideration and rely on sound, empirically supported research and analysis.
References
Bateman, A. L., & Salfati, C. G. (2007). An examination of behavioral consistency using individual behaviors or groups of behaviors in serial homicide. Behavioral Sciences & the Law, 25(4), 527-544.
Davies, A. (1991). The use of DNA profiling and behavioural science in the investigation of sexualoffences. Medicine, Science and Law,31, 95–101
Douglas, J. E., & Burgess, A. E. (1986). Criminal profiling: Aviable investigative tool against violent crime. FBI L. Enforcement Bull., 55, 9.
Douglas, J. E., & Munn, C. (1992). Violent crime scene analysis: Modus operandi, signature, and staging. FBI L. Enforcement Bull., 61, 1.
Grubin, D., Kelly, P., & Brunsdon, C. (2001). Linking serious sexual assaults through behaviour.London: Home Office
Hazelwood, R. R., & Warren, J. I. (2003). Linkage analysis: Modus operandi, ritual and signature in serial sexual crime. Aggression and Violent Behavior,8, 587–598
Schlesinger, L. B. (1999). Book Section: Essay and Review: Signature Killers. The Journal of Psychiatry & Law, 27(1), 191–194. https://doi.org/10.1177/009318539902700105
Keppel, R. D., & Walter, R. (1999). Profiling killers: A revised classification model for understanding sexual murder. International Journal of Offender Therapy and Comparative Criminology, 43(4), 417-437.
Woodhams, Jessica & Bull, Ray & Hollin, Clive. (2007). Case Linkage Identifying Crimes Committed by the Same Offender.
[1] According to discussions with Albrecht (26 July 2021), the NYPD and London’s Scotland Yard, among many major metropolitan police agencies, individually maintain detailed databases of modus operandi and suspected and identified perpetrators. Their general consensus is that criminal offenders do rely on a specific modus operandus when commiting their offenses and generally commit only one type of offence, e.g. robbery, burglary, larceny, etc.
About the Author: Burcak Unal is an intern with the IACS. She is a Criminal Justice and Law Enforcement Administration student with the Colorado State University, USA. Currently, she is based in Ankara, Turkey.
