Inside Serial Killer Data: Part One

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Have you wondered about serial killer data? Have you asked yourself “What do the demographics of serial killers look like?” or “Are there correlations between certain types of killing methods and motivations for killing?” Well you’re in luck because we’ve gotten our hands on some juicy serial killer data featuring pretty much anything you’ve ever wanted to know about serial killers. Though it must be said you should probably take a hard look at yourself if you’re a little too excited about this data.

This data comes to us courtesy of Enzo Yaksic, Director of the Murder Accountability Project and Co-Founder Northeastern University’s Atypical Homicide Research Group, who has been an expert in this field for decades. The origins of this data begin in 2010, when Yaksic first thought of creating an all-encompassing database on serial killers and their victims. Yaksic partnered with Radford University Professor Mike Aamodt to create and maintain what is now known as the Radford/FGCU Serial Killer Database. To read more about Yaksic and his work, have a look at this recent Boston Magazine profile.

This database contains information on 4,743 murderers and 13,105 victims going back to the beginning of the 20th century and is based on the FBI’s definition of a serial killer: “The unlawful killing of two or more victims by the same offender(s), in separate events.” It features expected attributes such as demographic and geographic information and more obscure traits such IQ level, birth order (oldest/youngest/only child), and whether or not a killer was teased in school. And given the subject material, the data also provides information on the gruesome acts committed by those killers on their victims such as necrophilia and whether or not the killers drank the blood of their victims.

So let’s dive in and see what kind of grim insights we can find.

Analysis

Demographics

First up we let’s take a look at the some of the demographic information of serial killers. The follow pie charts and histograms show gender and racial compositions of killers and their ages when they commit their first and last murders.

 

ages_plot

These three graphics give us a very clear picture of the demographics of serial killers. The vast majority of them are male and are either white or black. What I found a little surprising is their youth. The median age of a killer when he commits his first murder is 26 and the median age when he commits his last is 31. Half of their first kills occur between the ages of 21 and 33 and half of their last kills occur between the ages of 25 and 40.

Now let’s compare and contrast these graphs with their victim counterparts.

gender-vicrace-vit

victim-age

In terms of race and age, victims and their killers are relatively similar. Victims are somewhat more white and less black than their killers and slightly younger than them as well. The histogram of ages peaks in the lower 20s just like that of the histogram of ages of killers at their first kill. The median age of victims is 28 and half of them are between the ages of 20 and 44.

Motivations and Methods a.k.a the “How” and the “Why”

Our stereotypical image of a serial killer is a deranged individual who kills for pleasure with either his hands or an object such as a knife. It’s a profile reinforced by Hollywood as seen in films like Psycho and the Scream franchise. However as is the case with stereotypes, what we perceive is not completley accurate. The data shows that the profile of a serial killer is more nuanced than what we see on the silver screen or what haunts us in our nightmares.

The following two graphs display the distribution of types of motivations and the methods of killers in the dataset.

 

Motivations

motivation

Methods

The top motivation does validate the general conception of a serial killer by showing that the enjoyment is the most popular type of cause, though it is interesting to see financial incentive in a not too distant second. 80% of murders are motivated by either anger, financial reason or pleasure. While the methods chart overwhelmingly shows that guns are the most preferred medium of killing, thus dispelling to a certain the notion of slasher flick serial killer.

After examining the top methods and motivations of murders, let’s take a look at the top combinations of methods and motivation as shown in the following table.

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It appears that serial killers aren’t too picky when it comes to their methods of killing. 12 out of the 20 methods listed in the table involve multiple means of killing. What I find interesting is how shooting murders doesn’t correlate with pleasure-motivated murders as much as strangling, stabbing or bludgeoning. These are methods of killing that are for lack of a better term more “hands on” than shooting someone with a gun. Of the six entries in this table that mention shooting, only one of them corresponds with a killing motivated by enjoyment.

One thing I wanted to explore was whether there were significant differences among killers who killed for financial, pleasure, or anger reasons. When I looked at the data, I was surprised to see what I found.

  • When it came to gender, those who killed for financial incentives were 22% female as opposed to 5 for enjoyment and 9 and for anger.
  • White men comprised 60% of those who killed for enjoyment, while they made up 45% of those who killed for anger and 40% for financial reasons.
  • Financial killers had the highest average number of victims at 8.54 while enjoyment had 7.43 and anger had 3.95.
  • Average age of first kill for anger-motivated killers was 26 while the other two were 29.
  • When it came to sexual orientation, enjoyment-motivated killers had the lowest rate of heterosexuality at 89% while the other two categories clocked in at 95%.
  • Financial incentive killers had the highest rate being of married, coming in at 45% while the anger killers were married at a rate of 35% and enjoyment killers were at 33%

Stay tuned for part two where we closely take closer at the some of the other traits of the killers and take a deeper look at the victims.

 


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