Serial Killer Glossary

Angel of Mercy
A rare type of serial killer who is usually female and employed as a caretaker. The angel of mercy is often in a position of power and decides the victim would be better off if they no longer suffered. This person then uses their knowledge to manufacture the death of the victim. As time goes on, this behavior escalates to encapsulate the healthy and the easily treated.

Black Widow
A woman who kills two or more husbands or lovers for material gain.

Depravity Scale, The
Aims to establish societal standards of what makes a crime depraved, and to develop a standardized instrument based on specific characteristics of a crime that must be proven in order to merit more severe sentences.

Persistent bedwetting past the age of five.

Holmes Typology
A classification system for serial killers developed by Ronald M. Holmes and Stephen T. Holmes. Major categories include Power/Control, Hedonistic, Mission Oriented, and Visionary.

Linkage Blindness
The inability of one law enforcement jurisdiction to compare findings and evidence with another. This leads many killings to never be connected as being perpetrated by a serial murderer.

Mass Murderer
A person who commits multiple murders at one time.

McDonald Triad, The
A set of three behavioral characteristics that are associated with sociopathic behavior. The McDonald Triad consists of animal cruelty, obsessive fire setting, and persistent bedwetting past age five.

Modus Operandi (M.O.)
In criminal profiling, how an unsub commits a crime. The M.O. of a serial offender changes with the situation and over time.

Memorabilia centered around famous serial killers, includes the paintings, writings, and poems of these killers.

Sadistic pedophilia. Albert Fish is one of the classic examples.

National Center for the Analysis of Violent Crime (NCAVC)
A component of the FBI’s Critical Incident Response Group located at Quantico, Virginia. NCAVC provides behaviorally-based operational support to federal, state, local and international law enforcement agencies involved in the investigation of unusual or repetitive violent crimes, communicated threats, terrorism, and other matters of interest to law enforcement.

A behavioral and investigative tool that is intended to help investigators to profile unknown criminal subjects or offenders.

A personality disorder manifested in people who use a mixture of charm, manipulation, intimidation, and occasionally violence to control others, in order to satisfy their own selfish needs.

Serial Killer
While there are numerous definitions of the term, it generally refers to a person who murders three or more people over a period of more than thirty days, with a “cooling off’ period between each murder, and whose motivation for killing is largely based on psychological gratification. Believed to be coined in English by FBI Special Agent Robert Ressler in the 1970’s. The FBI seems to be moving more and more towards accepting of defining a serial killer as someone who kills two or more people, with the important differentiator being the cooling off period.

Serial Killer Cycle
The Aura Phase: The killer begins losing grip on reality
The Trolling Phase: The killer searches for a victim
The Wooing Phase: The killer lures the victim
The Capture Phase: The victim is entrapped
The Murder or Totem Phase: The emotional high for the killer
The Depression Phase: Occurs after the killing

In criminal profiling, why an unsub commits a crime. A serial offender’s signature generally does not change over time, without a change in the offender’s mental state.

“Son of Sam” Laws
Laws existing in some states that prevent murderers from profiting from the publicity generated by their crimes.

Spree Killer
A person who commits murders in two or more locations with virtually no break in between.

Events that trigger a killer into action.

Violent Criminal Apprehension Program (ViCAP)
A unit of the United States Federal Bureau of Investigation responsible for the analysis of serial violent and sexual crimes, organizationally situated within the Critical Incident Response Group’s (CIRG) National Center for the Analysis of Violent Crime (NCAVC).

An “Unknown Subject” and the initial object of a law enforcement investigation. Popularized by the television show Criminal Minds.