In the case of Nathanial Code, M.O. and victimology alone would have failed
to link him to each of the eight murders. But Code left more than gags, duct
tape, and bodies with gunshot wounds and slashed throats at the crime scenes;
he left his “calling card.” Investigators found this “calling card” or signature
aspect at every crime scene, and thus, were able to link Code to the offenses.
The Signature Aspect
The violent, repetitive offender often exhibits another element of criminal
behavior during the crime–the signature aspect or “calling card.” This criminal
conduct is a unique and integral part of the offender’s behavior and goes
beyond the actions needed to commit the crime.
Fantasies of offenders often give birth to violent crime. As offenders brood
and daydream, they develop a need to express these violent fantasies. When
they are finally acted out, some aspect of each crime demonstrates a unique,
personal expression or ritual based on these fantasies. However, committing
the crime does not satisfy the needs of offenders, and this insufficiency
compels them to go beyond the scope of the offense and perform a ritual.
When offenders display rituals at the crime scene, they have left their
individualized “calling card.”
How do crime scenes manifest this “calling card” or signature aspect? Basically,
crime scenes reveal peculiar characteristics or unusual offender input that
occur while the crime is being committed.
For example, a rapist demonstrates his signature by engaging in acts of
domination, manipulation, or control during the verbal, physical, or sexual
phase of the assault. The use of exceptionally vulgar or abusive language,
or preparing a script for the victim to repeat, represents a verbal signature.
When the rapist prepares a script for a victim, he dictates a particular
verbal response from her, such as “Tell me how much you enjoy sex with me,”
or “Tell me how good I am.”
The use of excessive physical force shows another aspect of a subject’s
signature. One example of signature sexual behavior involves the offender
who repeatedly engages in a specific order of sexual activity with different
The signature aspect remains a constant and enduring part of each offender.
And, unlike the M.O., it never changes. However, signature aspects may evolve,
such as in the case of a lust murderer who performs greater postmortem mutilation
as he progresses from crime to crime. Elements of the original ritual become
more fully developed. In addition, the signature does not always show up
at every crime scene because of unexpected contingencies, such as interruptions
or an unexpected victim response.
The investigator may not always be able to identify signature aspects. Violent
offenses often involve high-risk victims or decomposition of the body, which
complicates recognizing the signature aspects of an offender.
Modus Operandi Or Signature Aspect?
The following scenarios are fictitious accounts. They are used to show the
difference between a M.O. and a signature aspect.
A rapist enters a residence and takes a woman and her husband captive. The
offender orders the husband to lie face down on the floor and then places
a cup and saucer on his back. He tells the husband, “If I hear the cup move
or hit the floor, your wife dies.” The offender then takes the wife into
the next room and rapes her.