On Nov. 11, 2013, Miranda Barbour and her husband of three weeks, Elytte Barbour, collaborated in the murder of 42-year-old Troy LaFerrara. The pair lured LaFerrara into their car via a phony Craigslist ad, before strangling him and stabbing him to death — ultimately earning Miranda Barbour the morbid distinction of “Craigslist Killer.”

But that’s only the beginning of the story. On Saturday, the Sunbury, Pa. Daily Item reported Miranda Barbour had confessed to 22 other murders with her husband, all of which, she says, followed the same path as the first. A disciple of a satanic cult since the age of 13, 19-year-old Barbour has reportedly been killing ever since she first joined the group in her home state of Alaska. She’s killed in California, North Carolina, and Texas. And while the New-Age style of her Internet-spurred murders are uniquely repulsive, Barbour and her husband’s case may be textbook in the eyes of psychologists.

According to Francis Scarcella, the Daily Item reporter who spoke exclusively to Barbour through the jailhouse phone, the most alarming fact wasn’t the body count or the style of the grisly murders she and her husband committed. It was that “she said that if she got out she would do it again,” Scarcella said. In speaking with Barbour, Scarcella learned that Barbour could recall the exact locations of all the bodies she’s stashed around the country. "I remember everything. It is like watching a movie,” she told him.

By and large, the normal law-abiding citizen doesn’t casually boast about her ability to recall a murder as if it were a movie. The terminal, primal act of killing, it should hopefully go without saying, registers in most people’s minds as an unnecessary, undesirable act. We don’t have to kill to survive, nor are we compelled for the sake of sport. But Barbour’s alleged “thrill kills” (only one has been investigated so far) highlight what is perhaps a business-as-usual response among murderers to the otherwise unspeakable behavior.

“They all seem like ordinary people, but they all share one thing — a psychotic personality that gets a thrill from killing,” Dr. Kathy Charles told the Daily Record of serial killers. Charles is a forensic psychologist, which means she deals primarily in the business of working backward from crime scenes, constructing the criminal from loose pieces of information. Through her research on killers such as Ted Bundy and Harold Shipman, she’s found serial killers are often a breed all their own. “Their nervous systems are different from others,” she said, “in the sense that they don’t get a thrill from some of the things that normal people would.”

Many serial killers — Barbour included, if her confessions hold up — display personality disorders, Charles remarked. They are disassociated from the rest of society. Barbour told reporters from the Daily Item that she was molested as early as age 4 and exposed to murder by the time she was 13. Her first murder took place with the leader of the cult she would eventually join — the leader instructing Barbour to shoot a man who owed the leader money. When she denied out of fear, the cult leader put his hands around hers and they shot the man together, she said.

Barbour requested an interview while in jail so that she could explain herself, such as the fact that her victims were all “bad people,” including LaFerrara, who, Barbour said, “said the wrong things.” Barbour reportedly agreed to sex for $100 and told LaFerrara she was 16. If he had refused the offer with that new information, Barbour told reporters, she would have let him go.

Whether that claim, along with the 22 other murders she’s confessed to, is true is an ongoing mystery left up to investigators deployed in their respective states. But part of understanding why people like Barbour commit their crimes is first understanding how the serial killer’s brain works. And for that, the work is left up to people like Charles.

“Psychology is so important when it comes to breaking down the reason why a person has committed an offense,” she told the Daily Record. “If we don’t establish exactly why it happened then we can’t understand it properly ourselves.”