"No problem can be solved from the same level of consciousness that created it" (Albert Einstein)

    Arrigo (2006) makes a distinction between a crime scene analyst and a profiler -- anyone trained in police techniques can analyze the M.O. (crime scene analysis), but it takes a profiler to analyze the signature.  Likewise, and without making distinctions, Keppel (2005) discusses methods of determining M.O. (modus operandi) and signature as a process termed crime scene assessment, the most important component of which is a process called signature analysis.  The "signature" (or whatever the offender does beyond the crime, such as some form of binding, arson, unnecessary stabbing, and/or arranging of the crime scene) SHOULD be the major focus of investigators IF the purpose of the investigation is to determine if two or more crimes are committed by the same person.  Geberth (1994; 1996) adds that it is often not enough for many criminals to consummate their crime (murder); the killer must act out his fantasies in some manner over and beyond inflicting death-producing injuries, and this "acting out" is the signature, or characteristic of the crime which reflects a unique aspect (of the personality) played over and over again in fantasy.

    The M.O. (modus operandi) is best thought of as the kind of background factors which the offender thinks are helpful in carrying out the crime.  Some approaches to M.O. analysis, like the Scotland Yard method (which practically defined M.O. for many years), are totally objective and based on what are actually necessary to carry out the crime.  However, FBI (VICAP) profiling methods changed much of the way M.O. is estimated, and estimated it must be, because M.O. should certainly not be simply a collection of "facts" but a series of probabilities or hypotheses about the offender's "default settings" or life script, as Ainsworth (2001) calls it.  An M.O., properly estimated, reveals very much about the offender.  Surely, there is some overlap of M.O. with signature, as Canter (2000) acknowledges, and further, as Dale (1997) makes clear, an M.O. can evolve or change.  However, the M.O. is valuable at the very minimum as a class characteristic of socio-psychological traits which make up the typical offender for a specific kind of crime.  


    To truly understand the offender, more than just the crime scene needs to be examined.  Think of the criminal as an artist and the crime scene as their canvas.  Wouldn't you want to know more about the artist to better understand their finished product?  Profiling involves studying every behaviorally-relevant aspect in detail.  For example, a behavioral assessment is usually done of all the interactions between victims and offenders.  Significant events before, during, and after the offense are examined.  Key questions to be asked include: Why this victim? Why this day? Why this place? and Why this behavior?  These are the usual questions to ask when considering M.O. (modus operandi) and/or signature, but there is more to it than asking questions and/or looking for preparatory behavior on the part of the offender. 

    It all boils down to behavior, patterns of it, sometimes obtained through fragments of information. Behavior, it can be safely assumed, is what one does and how one does it.  No one has perfected the science of which behaviors are more reflective of personality than other behaviors.  A "pattern" of behavior can be similar to everyday, ordinary behaviors, but it can also be unique to the individual in question, and occur only sporadically.  Obviously, anything an offender says is important, but a man does not need to speak to a woman to rape her.  Violent crime involves many dynamics of human behavior.  From the offender's point of view, much of what they do when they are committing crime is acting normally, for them.  From another point of view, they are acting out on needs and patterns developed over the life course, some of which may be abnormal needs and patterns.  The crime scene contains many manifestations of these behaviors, needs, and patterns.  If there are repeated crime scenes (i.e., a serial offender), it is much more likely, with proper examination, that any unique behaviors, needs, and patterns will be uncovered.

    Three elements can link crimes in a series:
        1. the method of operation (modus operandi)
        2. ritual (signs of fantasy or psychological need)
        3. signature (unique combinations of behaviors)


    In general, modus operandi is the behavior necessary for the successful commission of a crime.  Douglas & Olshaker (1998:90) define M.O. as "what an offender has to do to accomplish a crime."  At a minimum, every M.O. will contain elements that involve the following: (1) ensure success of the crime; (2) protect identity; and (3) effect escape.  For example, when a criminal uses duct tape to cover a victim's mouth, this is M.O. because the criminal has realized the victim's screams for help might get him caught.  You cannot always link cases by M.O. because M.O. is dynamic and always changing with experience.  It's learned behavior like any other behavior, and involves things like experience, education, and maturity.  According to Keppel (2005), the phrase modus operandi first appeared in the literature in 1654 in a piece called "Zootmia: Because of Their Causes or Their Modus Operandi" but didn't make the leap from being a description of animal behavior to a description of human behavior until the 1800s when the term started appearing in English utilitarian literature (e.g., Mill's Logic).  In the United States, the phrase was for a long time used in patent law to describe the way new machine inventions worked.  By the 1890s, Scotland Yard detectives began maintaining modus operandi files to that the known habits of criminals could be traced from district to district (Fosdick 1916).  Over the years, the Scotland Yard method of maintaining modus operandi files became the method in police science, and file systems usually tried to record the following elements as Scotland Yard did:

    1. Classword (the kind of property attacked)
    2. Entry (the point of entry)*
    3. Means (any implements or tools used)
    4. Object (kind of property taken)
    5. Time (the time of day or any significance about the day)
    6. Style (whether the criminal described themself as someone else to gain entry)
    7. Tale (any disclosure by the criminal about themself)
    8. Pals (whether the crime was committed with confederates)
    9. Transport (how the criminal transported himself)
    10. Trademark (any unusual behavior in connection with the crime)

    The concept of modus operandi then found its way into some applied and theoretical criminology books such as Sutherland's (1947) Principles of Criminology where the following definition was put forward: "Modus operandi is the principle that a criminal is likely to use the same technique repeatedly, and any analysis or record of that technique used in every serious crime will provide a means of identification in a particular crime."

    The idea that a modus operandi could change, evolve, or vary slightly from crime to crime, appears to be a late 20th century development, and can be found in the writings of serial killer profilers like Douglas, Burgess & Ressler (1992); Dale (1997); and Hazelwood & Michaud (1999).  For example, Douglas & Olshaker (1998:90) say that "it is learned behavior and gets modified and perfected as the criminal gets better and better."  One take on this subject would hold that it seems the most change, evolution, or variation in modus operandi would occur with the element of "entry" where the offender changes how they gain entry upon discovery of more "hardened targets."  False change in the M.O. is also possible, involving the criminal seeking out a victim of a different race (or from a different geographical area) in order to throw any profilers off.  It is well-known that if M.O. files were the only thing police relied upon, authorities might think they're searching for more than one criminal.

    Ressler & Shachtman (1997) go a step further and say a profile based solely on M.O. would reveal a lot of things about society in general, like the way serial murderers are often fascinated by law enforcement.  This is all part of the FBI profiling approach which tries to ask "What kind of person would do this? -- man, woman, tall, short, etc."  Many offenders are avid readers of detective magazines (some even collect the lurid covers).  One serial killer, Gerard Schaefer, was even a police officer.  Besides being knowledgeable of police techniques, they will often have expressed an interest in becoming a private investigator, a professional photographer, and/or a locksmith.  Sexual serial killers will frequently have an impotence problem and have strong interests in: (a) powerful man pills, e.g., Viagra; (b) techniques to attract women; (c) meeting women by email; (d) ways to get fake IDs or fake degrees; (e) the power of witchcraft or anything similar representing the power of mind control.  They will have favorite porn stars (Vanessa del Rio is common); they will have favorite movies (Jeffrey Dahmer's was Hellraiser).  From this perspective, the M.O. tells the story of lifestyle choices and the pathways of living.        


    Ritual is behavior that exceeds the means necessary to commit the crime.  By definition, it is a subtype of signature sometimes called "ritual signature." It is fundamentally unusual behavior.  It may be based on psychosexual needs, and may be critical to the offender's fulfillment of their emotional needs.  Ritual may also be rooted in fantasy, and frequently involves paraphiliac behavior, or posing, overkill, and bondage.  You cannot always link cases by ritual because it may be constant or it may change.  In fact, ritual may simply be an attempt on the part of an offender to "stage" or "pose" the situation to shock authorities when they arrive at the scene.  Hence, it may or may not be related to behavioral aspects between the victim and offender.  The Crime Classification Manual (Douglas et al. 1992) says that ritual may evolve, but the "theme" persists.  As far as is known, not much academic study has been directed toward this "theme" element, with the possible exception of what is called "crime scene rhetoric" which usually falls into three categories: notes, wall writing, and body messages.  Notes are sometimes left at crime scenes and dump sites by the perpetrator, and their purpose is usually to taunt or insult law enforcement and/or the victims.  Some attempt to justify the murder; others predict future crimes.  Wall writing can be found on fewer occasions, and the content there is usually similar to messages left in other places or in notes.  Several serial killers, however, use the human body as a communications medium, either carving or writing on corpses, and sometimes parts of the body have been used in clever ways as signals or directions to find other concealed corpses.  


    In sum, signature is a combination of behaviors, emotions, and thoughts.  Douglas & Olshaker (1998:90) define it as "something the offender has to do to fulfill himself emotionally ... it is not needed to successfully accomplish a crime, but it is the reason he undertakes the particular crime in the first place."  Obviously, this can be inferred from both the M.O. and ritual (if present).  Signature is not the same thing as unusual behavior.  Ritual signature may be more likely visible since it is unusual, unnecessary behavior.  Such signatures usually put the offender at great risk because they must stay at the crime scene longer, so ordinary signature is often hard to detect.  At other times, it's obvious, such as when an offender goes to the trouble of leaving a Bible at the scene of the crime.  Sometimes, you'll have a combination of M.O. and signature, for example, when staging involves purposeful alteration of the crime scene in order to redirect investigation away from the offender.  Signature often involves "red flags" or inconsistencies that do not add up.  The following list summarizes some of the characteristics of M.O. and signature: 

M.O. = "success of crime"

I. Victim/location selection, means of attack, use of weapon, planning, means of transport

II. Valuables taken

III. Evidence left behind

Signature = "needs and patterns of offender"

I. Wound patterns, sex acts, means of control, rituals, talk

II. Souvenirs taken

III. Evidence destroyed

    The signature is sometimes called a "trademark" or "calling card" and reflects a compulsion on the part of criminals to go beyond just committing the crime to "express themselves" in some way that reflects their personality (not their whole personality in some psychological sense, but something about the addictive, repetitive, or compulsion-oriented part of their personality).  The core of a signature will never change (Keppel 2005), although it may get worse and worse over time (e.g., mutilation of the victim may increase from victim to victim).  Douglas et al. (1992) regard the signature as expressive of violent fantasies which progress incrementally over time.  Geberth (1996) adds that it is the long-term "acting out" of these violent fantasies which is the key signature element.  Frankly, this is the part of profiling which calls for the most retropective interpretation since it is very likely that these violent fantasies have been existing inside the criminal for many years, and are now only "bubbling up" to the surface.  It is to be expected that disagreements will be common among applied criminologists working the same case as to the exact nature of these fantasies and their developmental onset.  It is also important to note that a true signature may not evolve until after the offender has committed their second or third crime, although some signature elements may be present at the first crime.


    Keppel & Walter (1999) offer the following as the most outcome-based steps of the crime scene assessment process, aka the process known as "profiling" a case.

1. Determine the physical, behavioral and demographics of the unknown offender
2. Develop post-offense behavior of the offender and strategies for apprehension
3. Develop interview strategies once the offender is apprehended
4. Determine the signature of the offender
5. Determine where evidence can be located

    Turvey's (2001) steps are listed below, and are less stages of an exact procedure as they are a "cookbook" of the minimal ingredients to conduct a profile.

A. Crime scene video, photos, sketches, evidence logs
B. Autopsy video, photos, hospital, forensics, reports
Neighborhood data, maps, victim's travels, lifestyle
D. Investigative reports, witness statements
A. Equivocal Forensic Analysis
B. Corpus Delicti
C. Crime Scene Reconstruction 
D. Summary of Inputs provided to consultant
VICTIMOLOGY (Last 24-48 hours is important) 
A. Risk Assessment, Level, and Lifestyle
B. Sex, age, marital status, income source and amount, previous victimization, criminal history, mental stability, alcohol/drug use, physical handicaps, interpersonal relationships, family relationships, dating habits, sexual habits, reputation, leisure activities, type and number of friends, transportation used, future plans, and fears 
A. Injuries & Wounds, Victim & Location/Selection, Methods of Attack & Control, Victim Resistance, Sex Acts, Items taken, Verbal Behavior, Motive, Staging, Destruction
B. Modus Operandi
C. Disorganized/Organized
A. Signature
B. Motivational Typology
C. Hard & Soft Characteristics
D. Sadism/Fantasy
A. Consistency of Reports
B. Case Linkage
C. Task Force Management
OTHER IDEAS (Provocation Strategies, Thoughts about Remorse, Field Checklist)

    Others who have tried to outline the steps in profiling include Davis (1999) and Ressler, Burgess & Douglas (1998), the latter which appear below.

STEP 1: A comprehensive assessment of the nature of the criminal event and the offender types likely to have committed this particular crime.
STEP 2: An exhaustive and systematic assessment of the particular crime scene in question
STEP 3: A detailed and systematic review of the victims' backgrounds and potential suspects
STEP 4: An assessment of the likely motivating factors giving rise to the criminal event
STEP 5: The creation of a descriptive profile for the offender as linked to overt personality features gleaned from the criminal act or scene and associated with the assailant's probable psychological character

    Another attempt to outline the profiling process was made by Jackson & Bekerian (1997: 5) which is considered a fairly good systematization of the FBI approach.  These "stages" appear below.

STAGE 1: Data Assimilation -- collection of all available information from as many sources as possible (e.g., police reports, autopsy reports, photographs of the crime scene)
STAGE 2: Crime Classification -- an attempt to classify the type of crime on the basis of data collected
STAGE 3: Crime Reconstruction -- an attempt to reconstruct the crime and generate hypotheses about the behavior of victims, sequence of crime or modus operandi
STAGE 4: Profile Generation -- the generation of a profile including hypotheses about demographic and physical characteristics, behavioral habits and personality dynamics of the perpetrator

Deviant Crimes on M.O. versus Signature
Intro to Crime Scene Reconstruction
Modus Operandi of Female Serial Killers
NIJ Medicolegal Guidelines for Death Investigation

Practicing Psychology for Dummies
Serial Killers Dictionary Article
Turvey Article on Behavior Analysis

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Last updated: Aug 15, 2010
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