Why Spree Killers Kill Themselves

Photo: gcfairch / Flickr

With the Sandy Hook shooter dead, we may never fully understand why he gunned down 26 random strangers at a public school. Even when such killers have survived, their self-explanations have done little to shed new light on acts the rest of us can only grasp as psychotic. Inevitably, we are left with the bare facts of the attacks themselves to frame our understanding.

Such facts may be bare. But they are far from silent.

I recently conducted a study (currently in review) using binary logistic regression statistical tests and data from the 2010 NYPDreport of all identity-known active shooter incidents (n=179) in the U.S. between 1966-2010.

Here’s what I found: In about half of the “rampage” incidents (more than two casualties), the shooters killed innocent victims … and then committed suicide.

Why are some mass shooters more likely to kill themselves? If we go beyond the armchair psychology and diagnostic labels in the coverage of this horrific tragedy, the data from past rampage shootings (see also this paper and this related paper) may partially reveal some motivations.

It’s about self-loathing and perceived injustice. And location matters.

Psychologists have long theorized that there’s a connection between rage against others and rage against the self.

According to my findings, the shooter’s likelihood of committing suicide or suicide by cop appears to be 1.16 times higher (controlling for the attacker’s age and sex) for each additional victim that is killed. This suggests that those who have the most rage toward others – and therefore end up killing the most victims – would also feel the most guilty and ashamed about their crimes. They are therefore more likely to engage in “self-punishment” via suicide or suicide by cop. After the initial explosion of rage causes them to open fire, active shooters who see many dead or dying victims around them may feel a correspondingly higher need for self-punishment than shooters with fewer victims.

Besides killing more victims, active shooters who arm themselves with more weapons are possibly fueled by a more powerful sense of “injustice” and hopelessness than other active shooters. For each additional weapon a rampage shooter brings to the crime scene, his or her likelihood of dying is 1.76 times higher. This would also explain why they’re more likely to end up killing themselves.

Criminologist Jack Gibbs’s theory of social control suggests that when an individual commits murder, he or she does so because the social system is perceived to have failed in its responsibility to control the behavior of others and thus protect that individual’s rights. Unable to rely on broader instruments of social control, the murderer tries to “correct” past injustices by employing his or her own direct control over others, which manifests itself through violence.

Anecdotal evidence supports the theory’s application to many active shooters, who indeed claimed to have attacked in response to past injustices. Perhaps the same offenders who have the least hopeful perception of social control mechanisms – and thus need to exercise the most direct control themselves – also feel like they have the least to live for, because society is so terribly unjust. This interpretation would dovetail with previous theories of suicide that suggest that hopelessness is one of the most common reasons why people seek death.

These same concepts help explain why active shooters who attack in open commercial locations are particularly likely to end up dead. Because attack location makes a difference: Shooters who struck at sites such as shopping malls, department stores, and restaurants were 4.19 times more likely to die as a result of their attacks (compared to those in the NYPD’s “other” location category).

The biggest difference between attacking at open commercial sites and attacking at other locations is the nature of one’s victims: at open commercial sites, victims tend to be far more random and representative of a cross-section of society.

Gibbs’s theory of social control applied here suggests that offenders who attack random victims at open commercial sites are responding to perceived failures of social control at a societal level, and are thus the most universally hopeless about their future. In contrast, offenders who target victims at schools or office buildings would be responding to failures of social control at a much smaller level, and would not be as hopeless about society at large and therefore would have less desire to die.

The guilt, shame, rage, and self-loathing generated by active shooters who kill random victims may be even more overwhelming than the feelings experienced by offenders who kill a subset of victims at a specific location they view as particularly oppressive and corrupt.