We see it in the news all the time. The term ‘Serial Killer’ is used to describe pretty much any person suspected of more than one murder.

Those analysing a crime from a law or a psychology angle would probably agree that this term is bandied about too much. So what type of person fits the criteria of a serial killer? What is the difference between a mass killer and a spree killer?

Serial Killers

Definition: A serial killer is a murderer who kills three or more people, on separate occasions, with cooling off periods in between. They usually select their victims carefully, plan their crime and, more often than not, have a particular MO.

Jeffrey Dahmer is the perfect example of a serial killer. His seventeen victims were all male, and their deaths spanned across almost fifteen years. Dahmer is known for his heinous crimes, which include rape, torture, necrophilia and cannibalism. His MO consisted of subduing his victims, either through drugs or alcohol, then manually strangling them.

Dahmer is solidly in the serial killer category because of the period of time in which he killed, and because of his method of operation. Dahmer learned from each of his victims, perfecting his MO as he went. He also went to great lengths to hide his murders, dissolving his victims in acid to ensure that no evidence remained. This part, however, is ironic, as Dahmer couldn’t help himself and kept macabre trophies all over his house. This eventually led to his arrest.

Spree Killers

Definition: A spree killer is someone who kills two or more victims during a single event, at multiple locations. There is no cooling off period in between victims. The identity of a spree killer is usually known to authorities during the killing period, and so they become a fugitive while committing their crimes.

In May of 2014, Elliot Rodger stabbed his three roommates to death. He then got into his car, drove through Isla Vista in California, shooting at sorority girls, people on the street and striking pedestrians with his car. Rodger killed six people that day, and injured a further fourteen.

Elliot left a manifesto, explaining that his killings were ‘retribution’ for the constant rejection he received from girls. Rodger fits the description of a spree killer as all of his murders occurred during the same period of time, at different locations across Isla Vista. Once he began shooting at bystanders, police were notified and began their pursuit, which ended in Rodger’s suicide.

Mass Killers

Definition: A mass killer is someone that kills four or more people at one location, over a sustained period of time. The method of killing is usually the same, and the timing of the attack can last between minutes and days.

The names Eric Harris and Dylan Klebold have become synonymous with the term mass killer. In April of 1999, the pair of high school students spent almost an hour making their way through Columbine High, setting off bombs and gunning down anyone in their path. The total death toll was 15 (including both Harris and Klebold), with 24 others injured.

The Columbine killers fit the bill for mass killers as they carried out their attack with the aim of as many casualties as possible. Because they knew the school, Harris and Klebold were able to trap students in, in an attempt to increase the number of victims.

Hopefully this blog post clears up the differences between certain types of homicide. Is there a certain case which you know of that blurs the lines? Let me know in the comments.