Serial killers. Mass murderers. What’s the difference?

Serial killers. Mass murderers. What’s the difference?

By Meghan Cotterman - Guest columnist

On Dec. 14, 2012, 13-year-old Adam Lanza, who was the boy behind the Sandy Hook shooting, killed 20 students, six adult workers, and his mother, before turning the gun on himself. (, Lanza) Beginning in 1978, and ending in 1991, the infamous Jefferey Dahmer raped, murdered, and dismembered the bodies of at least 17 young males over a 13-year period of time. ( Some would say, they are one and the same. They are both murderers, correct? Not entirely. Up until recently, they all were considered the same. With the rise of mass shootings and the decline of active serial killers, criminologists and forensic psychologists recognize that they are very different. Characteristically, they fall into completely different categories of murderers with timing, numbers, motives and goals being key factors.

On the morning of Dec. 14, 2012, Adam Lanza shot his mother, then took her car and drove to Sandy Hook Elementary School. Once there, he opened fire, killing 20 children and six adults. (, Lanza) This killing spree would qualify him as a mass murderer. On the other hand, Jeffery Dahmer, over a 13-year period of time, sought out these 17 males, lured them into his home with bribes, and drugged them before killing them. (, Dahmer) This would qualify him as a serial killer.

A serial killer is defined as someone who kills three or more victims in a period of over a months’ time, with a “cooling down” time between the murders. To be defined as a serial killer, all of the killings must take place in a series of separate events. They can be grouped into four different categories, based on their characteristics: visionary, mission oriented, hedonistic, and power/control. ( Their ultimate goal is to take someone else’s life to fulfill their own fantasies and sociopathic tendencies, making their motives more obvious. The killer usually targets victims who all share the same type of characteristics, whether it be social or physical. They stalk and then target their victims. The type of violence inflicted on their victims also depends on the killers’ background. For example, some have a history of physical, emotional, and sexual abuse at a young age from someone close to them. Some do it for the thrill, sexual gratification, rage, financial gain, fame, or they just simply think society would benefit from the persons’ death. Whatever the reason is, serial killers are troubled people who kill for some type of gratification or purpose. They live each day to continue with their obsessions to kill, and often don’t stop until they are caught and apprehended by the authorities.

They are master manipulators and have a need for control. They must always be in control of every situation, and if they sense they are losing control, or appear vulnerable, they will turn to manipulation to maintain that power. Some are egotistical and tend to brag about their killings. While others are charmers or appear to be your everyday average Joe. This could be the most frightening trait of all. They come off as charismatic, charming, or as someone of trust to lure you in.

Mass murderers are defined as someone who kills numerous people, during an event, in a single location with no “cooling off” period between murders. While there are some exceptions, most mass shootings end with the death of the shooter, whether it be by law enforcement or by self-suicide. They can be grouped into eight different categories based on their characteristics: the discipline, the family annihilator, the disgruntled employee, the ideological, the set and run, the disgruntled citizen, the psychotic, and the school shooter. Most mass murderers tend to be young males, who spend time planning the event which will take place during the day, in a public place. Some suggest that these killers have problems with neurodevelopmental or psycho-social problems.

Mass murderers tend to be paranoid individuals with acute behavioral or social disorders. They have an inability to differentiate between right and wrong. Their perceptions are distorted, they tend to manipulate other people, and they become removed from society. They are resentful towards others due to imagined or real rejections, being bullied, humiliated, and/or outcasted. They are loners or social outcasts that have been pushed over the edge. For the most part, the motives of a mass murderer aren’t as obvious, but the ultimate goal is to act out their violent fantasies of revenge on a large scale that will draw big attention. They make a desperate attempt of revenge against society with no intentions of leaving quietly or going on to kill another day.

Both serial killers and mass murderers, often share some similar characteristics, but the differences highly outweigh the similarities, which is why they are in different categories. They both tend to be masters at manipulation, both lack empathy, and lack the value of a human life. Also, these crimes by both types of criminal offenders are considered premeditated.

Ultimately, what it comes down to, knowing the differences between a mass murderer and a serial killer, is details. The two biggest details being time frame and number of murders. There will always continue to be disagreements regarding the characteristics between the two. They are both qualitatively and quantitatively different, so instead of focusing on why the are different or the same, shouldn’t we be focusing on the phenomenon and why this is happening?

Works Cited

“Adam Lanza.”, A&E Networks Television, 7 Mar. 2018,

“The Most Prolific Serial Killers in American History.” Ranker,

“The Serial Killer.” The Mind of a Serial Killer | Criminal Minds Series,

“Serial Killers vs. Mass Murderers.” Crime Museum,

“Mass Shootings.” Gun Violence Archive,

“Serial Murder.” FBI, FBI, 21 May 2010,

“Serial killings.” Serial killings | World Problems & Global Issues | The Encyclopedia of World Problems,

Rivas, Anthony. “Serial Killers More Likely to Have Autism, Head Trauma, Or Psychosocial Issues – But Not All Who Suffer Are Killers.” Medical Daily, 21 May 2014,
Serial killers. Mass murderers. What’s the difference?

By Meghan Cotterman

Guest columnist

The writer lives in Fort Loramie and is sophomore at Edison State Community College. This column was written as part of her English Composition assignment.

The writer lives in Fort Loramie and is sophomore at Edison State Community College. This column was written as part of her English Composition assignment.