The news media and the pundits are wading through another fog trying to figure out why the latest serial killer went on a rampage. As a sociologist who has written on this subject before, I can attest that serial killers have much in common, and this is especially true of young killers.

To begin with, let's dispense with a popular myth about the latest tragedy. Contrary to what most are saying, Dimitrios Pagourtzis, the killer who shot his victims at Sante Fe High School, did evince warning signs.

Soon after 10 innocent persons were shot dead, Texas Gov. Greg Abbott said, "the red-flag warnings were either nonexistent or imperceptible." He was fed the wrong information.

A few weeks before the shooting, there were at least three perceptible signs of trouble: Pagourtzis made two alarming changes on his Facebook page, and, more importantly, he threatened to kill someone.

For example, he posted a picture of a black T-shirt on his Facebook page with the words "BORN TO KILL" on it. On the same day, he posted a picture of a jacket with genocidal symbols on it: the hammer and sickle of the Communist Party, and the Nazi Iron Cross of Germany's Fascist regime. These two postings were obvious signs that something was wrong.

Then there is the tragic case of Shana Fisher. Two weeks before Pagourtzis shot her, he told the 16-year-old student that he was going to kill her. She told both of her parents. According to her father, who did not live with either his daughter or his ex-wife (he had remarried 13 years earlier), "He [Pagourtzis] had told her himself he was going to kill her. He was walking around planning this in his head for weeks."

The father blamed Shana's teachers, saying, "If they are smart enough to teach our kids, they should be smart enough to see when something is badly wrong with someone." He did not say why he wasn't smart enough to do something, even though he, unlike the teachers, knew of the threat on his daughter's life.

When analyzing serial killers, it is important not to miss telltale signs. There are plenty of them. While any one of them, standing alone, may not be cause for concern, they become worrisome when spliced together. The fact is that serial killers evince a pattern of behavior that clearly defines who they are.

Last fall, Stephen Paddock killed 58 people on the Las Vegas strip, wounding hundreds of others (he shot himself as well). He was a loner, played videogames, had no relationship with his gangster father, and had no strong religious beliefs. A better example is Jeff Weise; he was 16 and Pagourtzis is 17. Paddock was 64.

In 2005, Weise killed his grandfather, his grandfather's companion, and nine of his classmates in the Minnesota massacre; he then killed himself. He was a loner whose father had committed suicide four years earlier, and was hostile to religion. In addition, he posted many messages on a nazi Internet site, loved heavy metal music, and was told by his classmates that he dressed like the Trench Coat Mafia who killed 12 students and a teacher at Columbine. In fact, he wore a black trench coat and combat boots.

What do we know of Pagourtzis? Besides his affection for Communist and Nazi symbols, he was known as a "weird loner" by his classmates; he lived in a mostly elderly neighborhood where children were almost nonexistent. As one young person who knew him put it, "He stuck to himself. He had a few friends but never really talked to many people." He also loved playing videogames and listening to heavy metal.

Pagourtzis did not see his father too often; he was typically overseas, working in the maritime business. Like Weise, Pagourtzis wore a trench coat (even when it was 90 degrees) and military boots. Similarly, his classmates liked to joke that he looked just like the Columbine shooters. He planned to kill himself but was apprehended by the police before doing so. He was also a professed atheist.

Most Americans do not know that Pagourtzis was an atheist, and that's because most of the media did not report it. Some reported that he was a member of a local Greek Orthodox Church. That's what the Associated Press, the New York Times, and USA Today reported, as well as the many newspapers that picked up their story.

The only big media outlets that reported on his atheism were the Los Angeles Times and the Washington Post.

No television station reported on his atheism. Not ABC, CBS, NBC, PBS, CNN, Fox News, or MSNBC (ABC and Fox reported that he danced at a Greek Orthodox church).

It goes without saying that if any of these serial killers had been a practicing Christian, the media would make sure the whole world knew about it.

The pattern is there for all to see: young serial killers are loners; they have a dysfunctional relationship with their father; they sport an affection for terrorist symbols; they wear military apparel; they imitate other mass shooters; they are drawn to the solitude of videogames; they love the crashing sounds of heavy metal; and they are either atheists or have no room for God in their lives. Sadly, they also have a wicked desire to kill themselves after finishing their victims.

Why do we have so many mass killers? It is true that they suffer from psychological disorders, which are made manifest in their traits. But unless we appreciate the role that boredom plays in their lives—killing excites them—we will never be able to figure them out.

"Among the forces that have shaped human behavior boredom is one of the most insistent and universal." That was the conclusion sociologist Robert Nisbet came to in his assessment of human history. "Although scarcely as measurable a factor in history as war, disease, economic depression, famine, and revolution," he said, "it is far from invisible in either the present or the past."

Boredom, Nisbet argued, could be relieved by "migration, desertion, war, revolution, murder, calculated cruelty to others, suicide, pornography, alcohol, narcotics." He added that "the pains and the results of boredom are everywhere to be seen, and nowhere more epidemically than in Western society at the present time."

He wrote that in 1982. For many sociological reasons, the curse of boredom has only worsened since then, finding relief in murder, calculated cruelty to others, and suicide.