We Asked a Psychologist How to Tell If Your Relative Is a Murderer

Dysfunction, unfortunately more often then not, is a key trait of the familial unit. Sisters are annoying, brothers are smelly, and parents just don't understand. This is witnessed by a wide range of films, TV shows, and books that trade in family discord for both comedic and dramatic effect. But as common—and fertile—as not getting along with one's family members may be, where does normal conflict start to blur into something more sinister? What causes occasional sparring and discontent to transform into the unredeemable tragedy of a Richard Yates novel?

That is the question a Reddit thread—"Relatives of murderers, what memories stand out as red flags?"—seeks to reverse engineer. In eerily stark comments, redditors discuss their friends and family members who have killed—most within their own home—and speculate on behaviors and attitudes that may have been prescient.

"My younger brother snapped and killed my mother and himself. He also tried and failed to go after my sisters, who were in the house at the time," a user named Foopacc writes.* After an argument with his mom that ended with a threat to commit him to a psychiatric hospital, again, Foopacc's troubled brother grabbed the gun that was in the house.

The Reddit user, answering the initial question, suspected that undiagnosed mental illness, a traumatic childhood, and a history of violence converged to play a role in making his brother a murderer:

Other stories on the thread involve chronic depression, childhood neglect, and a cycle of violence. Though one Reddit user, strawberrypops, points to a more distinctive turning point when her father's behavior darkened: "My dad attempted to kill my mum when she was pregnant with me. Apparently he was the nicest guy when they first met but he changed as soon as they were married. He became increasingly aggressive but the instance that made my mum [realize] that this guy might actually be dangerous was when he was driving my mum and my 2 older sisters (not his kids) somewhere. He was in a pissy mood and all of a sudden swung the car towards an old man who had just come out of a shop. The man thankfully managed to jump back in in time but there was no doubt that he'd have hit him otherwise. A total stranger. Just to try to frighten my mum and sisters. He did many things but that one always stood out to my family."

For another, there were no apparent warnings: "My dad shot my mom and himself when I was outside in the car. 5 times with a rifle to her face, once with a handgun to himself," a commenter who goes by the name vandancouver, who was six at the time, wrote. "I would have never thought of my father as a murderer. He was the best dad a child could have (it seemed). I remember two instances of him trying to hurt my mother, and at the time it was… normal? But now I realize something was wrong."

Individually, these stories are horrifying; collectively, they reveal that the threat of a supposed loved one is often only fully recognizable once they become a threat, especially for any children involved. Dr. N.G. Berrill, the executive director of the New York Center for Neuropsychology & Forensic Behavioral Science, says that while there are common threads that could provoke someone to murder their family, there aren't really generalizations that could provide a definitive type. "People will fight with one another, but the level of disturbance must be pretty profound when it becomes that desperate and that bizarre," he says. "They're not just the average person involved in a dispute. Typically it involves a protracted conflict, maybe a mix of jealously and paranoia, chronic depression. It's a confluence of events happening in someone's life such that they're overwhelmed and they believe the only thing they can do is something outrageous and violent. It's an act of bizarre control."

While it's possible to identify "red flags" in hindsight, they're not always easily identifiable before, Dr. Berrill says—even in his own practice. "Unfortunately, we had a patient who was sent here—not even for domestic violence or anger management—but for regular, individual treatment. During the course of treatment, very early on, he managed to kill his wife.

"Like everything, it's a case-by-case basis," he adds. "You can never know what someone is thinking if they don't share what they're thinking. But if someone is becoming increasingly paranoid and peculiar, if you care to look, you can see it. But people are very good at not sharing their most bizarre thoughts. You can never 100 percent know, and that's why I think the cliché about 'the serial killer next door' is true: He seemed like such a nice guy."

*Because these stories are posted anonymously on Reddit, Broadly cannot verify they are true.