Difference between a Mass murderer and a Serial killer

Updated on February 14, 2018

While mass murderers and serial killers are both groups of people known for murdering a number of victims, there is a difference between them. This article will explain that difference.


serial killer Ted Bundy
Serial killer Ted Bundy

A serial killer is a criminal who kills two or more people over a longer span of time, and often in different locations. The Federal Bureau of Investigation defines a serial killer as an individual who murders two or more people in different events, at different locations. Additionally, there will be a significant amount of time between each murder, often called a “cooling-off period.” There is also a psychological component to a serial killer: serial killings can be done out of thrill, anger, sexual desire, personal enjoyment, and so on.

One example is Ted Bundy, one of the most infamous serial killers in history, pictured above. Bundy killed 30-36 women between 1974 and 1978. He fits the criteria of a serial killer because he killed more than two people, and there was a significant amount of time between each murder.

Jared Lee Loughner
Jared Lee Loughner

A mass murderer is a criminal who kills many people at the same time or over a very short period of time, in one location, or multiple locations with little distance between them. The Federal Bureau of Investigation defines mass murder as the murder of four or more people during a single event. There will be little time between these murders, or in other words, there will not be a “cooling-off” period. There is also a psychological component to a mass murder: it can be seen as a release of tension, or a “blowing up.” While mass murders are done for reasons similar to serial killings, mass murders do not have the long-term planning and focus that serial killings do.

A recent example of a mass murderer is Jared Lee Loughner, pictured above. Loughner killed 6 people during the 2011 Tuscan shooting. Loughner fits the criteria of a mass murderer because he killed multiple people in one event, over a very short span of time.

Comparison chart

Serial KillerMass Murderer
Kills a number of victims over a longer period of time. Has a “cooling-off period.”Kills a number of victims over a shorter period of time. Does not have a “cooling-off” period.
Kills in more than one location, or during more than one event.Kills in a single location or during a single event.
Media attention not usually a motive.Media attention often a motive.

Serial Killer vs Mass Murderer

What is the difference between a serial killer and a mass murderer, then? The main criterion are whether or not there is a “cooling-off” period, the locations in which people are killed, and some of the motives that go into each crime.

Serial killers and mass murderers are, of course, both murderers, but a serial killer kills a number of people over a much longer period of time. Ted Bundy, for example, after killing someone, would sometimes not kill again for a month’s time. A mass murderer, on the other hand, kills a number of people in a very short span of time. Jared Lee Loughner killed 6 people in a single event, and was apprehended during that time. Another way to understand this distinction is to consider the following: if Loughner escaped and later killed others, he would be classified as a serial killer.

Additionally, mass murder is associated with a string of killings that occur in a single place during a single event, whereas serial killings refer to a string of killings occurring in different places during multiple events. Ted Bundy, for example, killed victims in Oregon, Utah, California, and Florida, among others. Jared Lee Loughner killed victims only in Arizona. If Loughner had killed in Arizona and then later killed in another U.S. state, he would fit criteria for a serial killer.

Regarding psychological motives, mass murder is usually done to draw some sort of media attention to the mass murderer, or to be put in the public eye for a variety of reasons, such as drawing attention to a cause the murderer takes fault with. Serial killers, on the other hand, do not often kill for media attention. Attention-seeking is a motive of some serial killers, but not to the same extent as a mass murderer.

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