The term serial killer was coined in the 1970s due to cases such as Ted Bundy and David Berkowitz. According to an FBI Behavioral Unit study 85% of the world’s serial killers are in America. At any given time 20 - 50 unidentified active serial killers are active.
Experts disagree on the definition of a serial killer but general definitions are based on numbers and patterns. Two or more unrelated victims in distinctly separate incidents.
Prostitutes, runaways and transients are usually not promptly reported missing receive little police or media attention, making them targets.
Experts speculate unsolved serial killings that appear to stop may be due to death, institutionalization, relocation or stopped killing. Some turn themselves in.
The Northwest has a notorious history of prototype killers — among them are Ted Bundy and theGreen River Killer. Lesser known serial killers charged and/or convicted of one or two murders are often suspected of more.
A serial killer with Antisocial Personality Disorder may appear normal or charming, (“mask of sanity”). Sometimes there is a common sexual element to the murders such as gender, occupation, appearances, race, etc.