Are serial killers born or made?

Paul LaRosa is a "48 Hours" producer. "Serial Confessions" airs Saturday, June 23 at 10/9c on CBS.

Are serial killers like Todd Kohlhepp of South Carolina just born bad or did something happen when they were young?

In this case, Kohlhepp, a formerly successful realtor, has pleaded guilty to killing seven of his fellow citizens. Kohlhepp denies he's a serial killer. In hours of police confessions, he tries to explain that he's basically a good guy who does bad things to people who cross him.

But even he admits that by definition, he fits the bill and, in his case, he has a history of bad behavior dating back to when he was a child.

After reviewing court documents, CBS New consultant Kris Mohandie, a forensic psychologist, says Kohlhepp was troubled from the age of 15 months. According to documents, he was a terror as far back as nursery school. He hit other children and destroyed their projects.  He shot a dog with a BB gun and used bleach to kill a goldfish.

"As a young child," Mohandie says, "he was already out of control, already into gratifying his power and dominance needs, already comfortable hurting other people."

Todd's mother, Regina Tague, remembers a smart boy who liked to read the encyclopedia and sit on her lap while she read the funny papers to him. "And he would laugh and he would get tickled. And he learned," she said.

But Regina and Todd's father divorced when Todd, an only child, was 2.  She remarried the following year. According to later psychological reports, Todd did not get along with his stepfather and grew increasingly hostile and abusive.

That might have been a turning point for Todd.

In "The Anatomy of Violence," University of Pennsylvania criminologist Adrian Raine finds research to indicate that when children are separated from parents before the age of 3, they are more likely to show signs of a psychopathic personality at the age of 28.

Another college professor, James Fallon, a neuroscientist, says he was shocked when he examined his own brain scan and realized it contained all the markings of a psychopath. In his book, "The Psychopath Inside: A Neuroscientist's Personal Journey into the Dark Side of the Brain," Fallon admits his shock as he then researched his ancestry and discovered seven alleged murderers in his own family tree going back generations. He believes he escaped a similar fate because of his parents' devotion toward him.

Kohlhepp's mother admits the divorce hit young Todd hard. He became increasingly difficult and she tells CBS News correspondent Davidl Begnaud: "If he didn't like something I did, he'd find a way to get back at me. One time I did something and…he stuffed all the bath towels down the commode and stopped it up, and flooded the house.

"I knew something was wrong inside."

She sent him to live with his father in Arizona but it did no good. Kohlhepp became increasingly difficult and more or less tortured other kids. He once locked a boy in a cage and a neighbor described him as "a devil on a chain."

When he was 15, his behavior became criminal. Kohlhepp kidnapped and raped -- at gunpoint -- a 14-year-old girl who was a neighbor. He let her go and he was soon arrested.  He was charged as an adult,  pleaded guilty to kidnapping in exchange for getting the sexual assault charge dropped. Still, he served 15 years behind bars.

When Todd Kohlhepp was released, he moved back to South Carolina and, although a registered sex offender, he was allowed [it was legal then] to get a realtor's license. He built up his business, dated, bought an upscale home and even got a pilot's license but his past behavior followed him.

Last year, he confessed to killing four people at a motorcycle shop because he perceived they were treating him rudely. Eventually, he admitted killing seven people total, as well as kidnapping and raping Kala Brown whom he held for two months inside a storage container with a chain around her neck.

Could Kohlhepp have escaped his ultimate fate? Given the research, the answer is maybe. Professor Fallon, by all accounts, has lived a law-abiding life, but had his upbringing been different, he believes he could have followed in the path of his relatives and, as he recounts in his book, he cheats at board games and is not always a nice person.