Training >> Browse Articles >> Investigations


Modus Operandi Vs. Offender Signature

Noor Z. Razzaq

Many aspects of forensic psychology (behavior analysis) are used to identify suspect(s) of violent crime in modern police investigations. The two most basic aspects of measurable and identifiable criminal behavior in the field of forensic behavioral analysis are modus operandi (MO) and offender signature. In order to perform effective investigations of violent or serial crime, investigators should have a rudimentary understanding of these basic profiling concepts beyond the realm of common usage, or rather misuse. This article will focus on the characteristics and differences between modus operandi and offender signature and why this understanding can be integral to violent crime investigations.

All criminals have a MODUS OPERANDI consisting of techniques, habits, and peculiarities in behavior which are performed with three basic objectives (Turvey, 2002):

1. Complete the crime

2. Affect escape

3. Avoid capture (e.g., investigation)

Serial offenders modify and perfect their MO as they become more adept at what they do. The improvement or slight adjustment to an offender’s MO is something for investigators to bear in mind in analyzing a criminal pattern over time and formulating a behavioral profile. This is especially true in the first stages of profiling when the investigator begins his or her profile from the paradigm of the Organized/Disorganized continuum. While offender MO pertains to the methods used to commit a crime, offender signature has a much less pragmatic role for the perpetrator.

OFFENDER SIGNATURE can be broken down into two separate but interdependent halves: signature aspect and signature behavior. Signature aspect defines the theme or motive of an offense, and can include motivational categories such as profit, anger, retaliation, assertiveness, sadism, and et cetera (Turvey, 2002). Signature behaviors, on the other hand, are committed to satisfy the emotional and psychological needs of the offender and usually define the theme of a crime.

The common challenge in distinguishing the MO from offender signature lies in the fact that certain offender actions committed in the act of the offense may satisfy both the offender’s MO and his or her signature. The key to determining which behavior falls into what category lies in the totality of the circumstances surrounding the offense. An example would be a rapist who covers his face. The act in and of itself could be an MO behavior in that the rapist may be attempting to conceal his identity. It could also be classified as offender signature in that covering his face enhances the sexual pleasure he may derive from the rape scenario in itself.

However, in profiling a burglar or bank robber who covers his face with a mask, the investigator could assume the action to be primarily MO due to the fact concealment of identity is integral to the completion of the crime without being caught. Differentiating between MO and offender behavior in other types of crimes may be a little more obvious. For example, MO behavior for an arsonist could be if he leaves his car running near a building he is about to set fire to in order to affect a quick escape. An offender signature for that arsonist would be to return to the scene of the crime and watch the havoc subsequent to the arson in order to experience pleasure, sexual or otherwise.

Although a sometimes confusing and often neglected subject, it is absolutely imperative for violent crime investigators to have a rudimentary understanding of the concepts behind ‘modus operandi’ and ‘offender signature’. The virtual impossibility of two or more offenders fitting the same modus operandi and the signature behavior(s) while operating in the same geographic area at the same time is the key to the importance of this understanding. Ultimately, it is up to the investigator to effectively analyze the totality of the circumstances surrounding the offense in order to make determinations regarding the classification of these behaviors. Once classifications are made, further profiling can be conducted allowing for one more tool to be used in further narrowing of the suspect pool and the building of a case against the offender, ultimately resulting in a quicker resolution to the investigation.


Turvey, B. (2002). Criminal Profiling: An Introduction to Behavioral Evidence Analysis (2nd Ed.). London, UK: Elsevier Academic Press.

Meyer, C.B. (2000). Introduction to Criminal Profiling. Retrieved April 9, 2007, from:

Copyright © 2008 by Noor Z. Razzaq. All rights reserved.

  • Photo_user_blank_big


    about 4 years ago

    so informative and so clear..thanks-

  • Acc_max50


    about 4 years ago


    Helpful and interesting

  • Jeso_max50


    about 4 years ago


    Bump razzaqnz, well said.

  • Photo_00002_max50


    about 4 years ago


    Good review of basic concepts. LTC Tom Nugent

  • Me_and_the_kids_1_max50


    almost 6 years ago


    "NPDCOP"...I have students that reference this page and you know better. Making up a profile and taking baseless "anonymous" jabs (if it's not clear yet, I know who this is) is both cowardly and unprofessional. Also to be clear, this article is an academic reference for LEOs/student. That requires one to cite sources (e.g., basic English writing 101). Additionally, please look up racial profiling and then offender profiling as they're clearly not the same thing (e.g., "experienced investigations" 101). Next time please come to me directly if you have some sort of an issue.

  • Dnc_shirt_max50


    about 5 years ago



  • Photo_user_blank_big


    almost 6 years ago


    Although the authors experience and bio sound very impressive, it didn't mention whether or not he actually worked any of these crimes. It is nice to have training, but training is as useless as the paper that the certificate is printed on until the techniques learned are put to practical use. I see you cited several sources, so as a real investigator who has worked these types of cases it appears that you regurgitated someone’s else’s work product. It sounds as if the author, who appears to be a minority, is speaking about the inappropriate use of profiling as an investigative technique, however since he was never an investigator what would he know of what tools are effective or not. I am disappointed that this article was published.

  • Photo_user_blank_big


    almost 6 years ago


    Very interesting and informative, thank you.

  • Photo_user_blank_big


    about 7 years ago


    Good for you Noor - Bert ....your former Forensic Behavior Analysis instructor.

  • Img_0557_max50


    about 7 years ago


    Nice to see what that abriviation meens

PoliceLink School Finder

Save time in your search for a degree program. Use PoliceLink's School Finder to locate schools online and in your area.

* In the event that we cannot find a program from one of our partner schools that matches your specific area of interest, we may show schools with similar or unrelated programs.

Recent Activity

36TR posted in: "Transfer of probation", 5 minutes ago.
dolphinblue gave a thumbs up to The Topic "How true this is", 39 minutes ago.
bill9823 gave a thumbs up to The Post "Poll: Well, So What We Gonna Do NOW???", 42 minutes ago.
JorgeGAI posted: "Transfer of probation", about 1 hour ago.