What is a serial killer? The term serial killer used to have a distinct connotation; a connotation that has changed over the years. According to the early editions of the Federal Bureau of Investigation's Crime Classification Manual, a serial killer was defined as there must be at least three murder events at three different locations, with a cooling off period between events, and they usually kill for psychological reasons.

However, this definition has changed over the years. Other criminologists have said that there only be need two killings to define a serial killer and in some cases, the serial killers have murdered multiple prey in the same location.

The term serial killer was never placed on any one killer in the United States until David Berkowitz also known as Son of Sam was murdering couples in their cars in New York City during the infamous summer of 1977. I say infamous because that is also the summer that New York City suffered from a huge blackout with looting and arson in July, during the time that Berkowitz was on the loose. Berkowitz started his campaign of killing in 1976 but continued through most of the summer until his capture at the end of July.

The term serial killer is not to be confused with the terms mass murderer and spree killings, although the F.B.I. Did away with the term of spree killer some years ago and has since lumped those murder events under the serial killer nomenclature. A spree killer was defined as a series of murders over a period of days and weeks, in different locations, but without the cooling off period as described in the definition for serial killers. A mass murderer is defined as someone who kills four or more people at one time in one location.

Here are some examples of the killers and their definition of crimes:

As I wrote before, David Berkowitz was considered a serial killer as was Jack the Ripper and Ted Bundy. Charles Starkweather killed eleven people in a two month period in December 1957 and January 1958 in Nebraska and Wyoming and Andrew Cunnanan murdered at least five people, including fashion designer, Gianni Versace, in a three month period in 1997. These two fell under the term of spree killer and two boys named Dylan Klebold and Eric Harris killed themselves and thirteen other people in Columbine High School in 1999. These two fall under the mass murder category.

Although most of the serial killers have psychological reasons for killing, some kill to rob people, some kill out of lust, some, like Berkowitz, killed for just the thrill of doing it, although he said he was obeying the orders of a demon that came in the guise of a neighbor's dog named Harvey and the neighbor's name was Sam and was eventually captured because of a parking ticket.