What is the difference between a serial killer, spree killer and mass murderer?

Police in Tampa, Florida, think they have a serial killer on their hands, after the shooting death of three people over an 11-day period in the same neighborhood, but do they?

Federal authorities and criminologists actually classify people who kill more than one person into three different groups: serial killers, spree killers and mass murderers.

The dictionary defines a serial killer as "a person who kills more than one victim in more than one location in a very short period of time," but according to the FBI that definition actually reflects the behavior of a spree killer.

A spree killer is someone who kills two or more victims over a short period of time without a cooling-off period, the FBI said. At this point and with what we know about the case, it seems this description fits the killer in the Tampa shooting deaths better than serial killer.

Spree killers don't resume their normal lives in between killings like serial killers do, according to Psychology Today.

“The maximum duration between murders in spree killing is generally considered to be seven days. Serial killers, on the other hand, may cool off for weeks, months and, in rare instances, even years between murders,” the magazine reported.

The lack of a cooling-off period is the difference between a spree killer and a serial killer, the FBI said.

"This is very different than serial killers who are much more likely to stalk and target complete strangers who somehow fulfill deranged and secret fantasies that only they understand," Psychology Today reported.

The D.C. sniper case from 2002 is a good example of a spree killing when 10 people were killed over 23 days by two shooters.

A mass murder is defined as the killing of a large number of people, usually in one place, like the attack in Las Vegas earlier this month when 58 people were shot to death from a window of the Mandalay Bay Resort and Casino.

Cox Media Group