Thailand- The pervy predator charged last week with the killing of 6-year-old JonBenet Ramsey cruised middle schools as a young man, meeting and marrying two child brides, Quientana Shotts, 13, and Lara Knutson, 16 – both of whom he traumatized.

John Mark Karr was so smothering and jealous that friends say when Lara became pregnant with twins, which the couple wanted to name Angel and Innocence, he refused to take her to the hospital. The twins died in childbirth.

“He was afraid the doctors would ogle her,” said a classmate who lived nearby and would only be identified as Renae. “She was very pretty and he was obsessed with her. He had to be right next to her at all times.”

Shortly after their wedding, Karr brought Lara back to the town he grew up in, Hamilton, Ala. – much to her parents’ alarm.

Although Karr projected an easygoing persona to some, pals who knew the couple in the tiny northwest Alabama town said he had a dark side that exploded in private.

They say he didn’t work and they suspected he used drugs.

After the birth of the couple’s first son, John, Karr threatened to kill Lara and the child, says Renae.

She often escaped to a nearby graveyard.

“Lara would run up into Rocky Grove cemetery at night and hide from him,” she said. “Other times she’d come over to my house crying. She’d bring some cookies or fudge, but would be afraid to eat them. She thought he was trying to poison her.”

“He was so obnoxious and controlling,” said Renae. “Once, after their third son was born, I went over there and he was so zonked out it took him 10 minutes to answer the door.”

He also forced her to scrimp – although he tried to put on a successful image for outsiders.

“We always wondered where he got his money,” said another neighbor who spoke confidentially. “[He had a] DeLorean, he had a red Porsche 924.

“At the same time, he was making Lara wash the kids’ diapers by hand because he refused to buy disposables.”

It wasn’t the first time that Karr had sought out and married a young girl.

In 1984, after dropping out of high school his senior year and then earning his GED, Karr married Shotts.

She filed for annulment within months, stating in court records that she “fear[ed] for her life and safety.”

“Quientana told friends she was disgusted by the ‘weird sexual things’ John asked her to do,” said Kim Wooten, who grew up a few houses down from Karr.

Despite telling classmate Bruce Thompson he was “horribly upset” by the annulment, Karr seemed to transform himself into a wild party boy with a fast car.

“One day he showed up in a DeLorean – the same car Michael J. Fox had in ‘Back to the Future,’ with Georgia plates that said ‘J KARR,’ ” classmate Alan Avery told The Post. “He also had the Ray-Ban sunglasses – a whole Tom Cruise thing going on.”

“That car gave him a whole new personality. Suddenly he was more outgoing and confident,” he said. “Cars and music were all he cared about. He’d blast Journey, Van Halen – all those ’80s supergroups – from the DeLorean.”

Others who knew him during his formative years said he was a charity case who drove exotic sports cars – cruising for pre-teens in the schoolyard.

Born 240 miles away near Atlanta, Karr and his older brother, Mike, were sent to live with their grandparents in Hamilton in 1976.

Their mom, Elaine, had perished in a car crash when John was in second grade. John was 12 when they moved to Hamilton; Mike, 17.

“John’s grandparents were way too old to raise those boys,” said a Karr relative.

But “their dad couldn’t care for them anymore. He had to work too many hours,” said classmate Toni Glenn of Wexford Karr, a well-to-do General Motors executive.

“John would occasionally go back to visit him in Atlanta, but my sense was that the relationship was strained and tumultuous,” said classmate Stephen Raburn.

Karr’s relationship with his mother may have been equally strained. When Karr was just a baby, she was institutionalized, apparently for postpartum depression.

And while corresponding with Michael Tracey – the University of Colorado professor whose e-mails led investigators to track him down in Thailand – Karr wrote that his mother “tended to raise [him] as a girl.”

Although always a loner, Karr was well liked at Hamilton MS. Some in town even took pity on him – “though in a nice way,” Thompson said.

“He never seemed to have any money. His grandfather had worked in a cotton gin and their house was lower middle-class at best,” said Glenn.

Thompson, whose family owned a local menswear store, recalls his mom giving Karr new clothes and hand-me-downs whenever he needed them.

At Hamilton HS, where he played trumpet in the band and sang in the choir, Karr’s hotshot persona began taking shape.

“He began dressing preppy. He was always immaculate. Every hair in place. He thought very highly of himself,” Avery said.

But behind the affable character seemed to lay the makings of a fiend – who wanted nothing to do with strong or aggressive women.

Beth Pearce recalls horsing around with Karr on campus one day – and messing up his feathered ‘do.

“He slapped me and knocked me down the bleachers,” she told her sister.

But Susan Cobb – who describes Karr as “passive-aggressive” and “extremely controlling” – would have none of that.

At the end of junior year, she went head-to-head with him for drum major. But Karr tried to stack the deck by performing with a flag girl, sophomore Tanya Evans.

“He thought that would clinch it for him. But when I won, he threw a hissy fit. He screamed so much that Tanya started crying like a baby,” Cobb said.

That dark side of Karr could be seen in the drawings Karr busied himself with while off alone. “They were always these odd, gothic-like pictures,” said Thompson.

Similarly, Karr went through a phase when he was fascinated with the macabre.

“He told everyone he was going to own the Hamilton Funeral Home one day, and made it a point to sign my yearbook on the page that had the funeral home on it,” said Raburn.

Like most at Hamilton HS, Raburn couldn’t recall Karr ever dating.

“He only seemed interested in younger girls – meaning junior high,” said Raburn.

Cobb also says that, although Karr never drank and was not seen partying around town, word was that he got high on painkillers and smoked dope.

Karr, by contrast, was an honors student, although he dropped out early in his senior year.

Louis Goggans, who was principal at the time, says he has no idea why. But one of Karr’s classmates, who spoke confidentially, said Karr had been asked to leave after being caught “holding hands with and kissing” a 13-year-old girl at the middle school.

A year later, in 1984, he married Shotts.

After their split, Avery said Karr would cruise over to the middle school – right at 1 p.m., when the kids were outside for phys-ed – to flirt with seventh- and eighth-grade girls.

Karr also began substitute teaching at nearby high schools, but was fired from two of them for the same inappropriate behavior with young girls that allegedly got him booted from Hamilton HS.

In 2001, Karr moved his family to Petaluma, Calif. Lara filed for divorce within months.

In court papers, she charged Karr with being manipulative and cruel.

He “purposely set about to get me pregnant so we could marry without parental consent,” she wrote.

“[He] insisted I cut off ties with my family and friends,” she continued.

Then, when she miscarried – he blamed her.

“He blamed me for a miscarriage,” she said. “A 16-year-old bride, I didn’t know any better than to give in to his demands.”

In other reports about the sensational case yesterday:

* Karr was expelled from Thailand, and was to fly out of Bangkok to Los Angeles tonight, where he’ll stay for an undetermined amount of time while his extradition paperwork is processed.

From there, he’ll be taken to Boulder, Colo.

* Reports say the investigation of Karr didn’t really begin until after his bust in Bangkok.

Although the Boulder County district attorney’s office had enough undisclosed evidence to get a judge to order Karr’s arrest in Thailand on a first-degree murder count, it was only after the warrant was issued that investigators started asking questions experts say would form the bedrock of a successful homicide prosecution, the Denver Post reported.

* JonBenet’s father is so unsettled by the renewed attention that he’s considering moving out of the country, a family lawyer said.