When Jim Clemente walked into the Bronx home of his former summer camp director, it wasn’t for old time’s sake.

The twenty-something Clemente was wearing a wire. Federal agents and an NYPD detective were listening in.

And his old camp boss, Michael J. O’Hara, was showing Clemente pictures of kids he’d molested — just like he’d abused Clemente a decade prior.

“I was scared to death while I was there,” Clemente, now 59 and retired from a storied FBI career, recalled of the 1986 meeting.

Clemente had convinced the predator he was a kindred spirit and had to keep his cool, or the criminal case being built against O’Hara — a Boy Scout leader, Catholic school teacher and youth-basketball coach believed to have sexually abused hundreds of kids — would fall apart.

The meeting was his sixth in three months with the violent, intimidating drunk from Long Island with the perpetual “sh-t eating smirk,” Clemente remembered. O’Hara had plied a teenaged Clemente with beer and violated him while they were alone at the Catholic Youth Organization camp in upstate Godeffroy.

Clemente at the time of the O’Hara investigation was a fledgling Bronx Family Court prosecutor. He would go on to become a criminal profiler for the feds, to his present career as a TV writer for the show “Criminal Minds.”

His quest for justice began in 1985, with a TV movie about incest.

“My brother called me. He had seen the movie, ‘Something About Amelia,’ and I think Ted Danson played a sex offender. He said, ‘We should do something about the director at that camp we were at,’ ” Clemente said.

His sibling revealed he’d once snuck into O’Hara’s office to find “two paper bags filled with pictures of him molesting boys.”

“I said, ‘Oh God, I thought I was the only one.’”

‘I went in the shower, and I turned the light off … and I just cried. That was the day I kind of withdrew from everybody.’

When he asked his brother why he never told him, Clemente’s brother said O’Hara somehow suspected he’d seen his secret stash and pointed a rifle at him, pulling the trigger until the gun clicked.

“It would be that easy,” O’Hara sneered.

Strangled by shame and fear, Clemente could only confide in his high school guidance counselor, a priest, Father Frank Stinner, about the abuse.

Stinner’s reply stunned Clemente.

“Say 10 ‘Our Fathers,’ and 10 ‘Hail Marys.’ I absolve you of your sin. Don’t ever speak of this again.”

He kept silent for a decade. But after the fateful conversation with his brother, Clemente called the FBI-NYPD Joint Task Force on Sexual Exploitation of Children.

“As I was telling the story, I started shaking, shivering,” he said. “I was 15. It was my first time ever being away from home.”

O’Hara was a “tough love” authority figure who hit kids and shot his rifle off without warning. He had Clemente stay with him alone in the woods to help close the campground.

O’Hara complimented him, took him out, handed him booze. He started talking about sex.

“I was really embarrassed. I didn’t know he was manipulating me. Eventually he molested me, and he did it again and again.”

When O’Hara returned Clemente to his Goshen home, he forced the teen to shake hands as they parted.

“I went in the shower, and I turned the light off … and I just cried. That was the day I kind of withdrew from everybody.”

His mom always suspected something.

“She’d say, ‘Jimmy, you used to be such a happy kid, what’s wrong?’ … I never told her before she passed away from cancer.”

Months after he reported O’Hara, the task force needed Clemente’s help.

“I was no like no f—-king way! I can’t sit down and have a cordial conversation with this guy!”

But his answer changed the day he visited his alma mater, Fordham University — and saw O’Hara, sitting at a desk in the registrar’s office.

“It makes my skin crawl,” Clemente recalled.

O’Hara knew Clemente had graduated from Fordham Law School and it appeared he had been keeping tabs on him. But it was the predator’s parting words which sealed his fate.

“Oh yeah, I was sorry to hear about your mother’s death,’” Clemente remembered. “It creeped me out and it pissed me off. I called the FBI and I said, ‘I know where he is, wire me up.’”

‘The detective met me and they took off the wire and I immediately ran to the bathroom and puked my guts out.’

On the advice of investigators, Clemente enticed O’Hara to a meeting, saying he needed to talk and O’Hara was the only one he could turn to. They met Halloween night, 1986.

“My heart was racing. [The agents] came to my house to wire me up. They were late. They gave me this sort of pep talk and instructions.

“I can remember vividly, hearing my own footfalls as I was walking down the street … conscious of every single sound. I can remember people in costumes walking across the street. It was so bizarre. It felt like there was a billion-watt searchlight pointed at me.”

They shared a booth. O’Hara quickly ordered a beer, and flung an insult just as fast when Clemente was slow to join in.

“You always were a wimp,” O’Hara said.

O’Hara got straight to the point: “‘This is about sex, right? It has to do with what happened between us?’”

A disgusted Clemente recalled how O’Hara talked about the molestation as if “this was something we decided to do together.”

O’Hara, then 43, shared his horrific legacy: he’d been a pedophile since he was 19, working at a Queens orphanage where he sought out the night shift to have access to kids, he told Clemente.

“He bragged about it. He bragged about boys I knew at the camp, he literally went through the list — he had dates and times and places, first names. All well beyond the statute of limitations, which was five years at the time.”

They spoke for three hours. Clemente had to leave by then because the tape in his recording device was about to run out.

“The detective met me and they took off the wire and I immediately ran to the bathroom and puked my guts out.”

It was half a dozen meetings before Clemente was able to help steer investigators to victims at a school at Hastings-on-Hudson. The recent cases would be viable in court.

As O’Hara gleefully showed off evidence of his crimes in their final face to face, including the photos, Clemente stood in the dumpy brick duplex and palmed two of the pictures and slipped them into his back pocket.

O’Hara soon after the meeting disposed of the cache of 500 photos, so the two images Clemente lifted became crucial evidence in the case.

O’Hara was arrested 1987 and convicted on a child pornography charge. He was sentenced to a year in jail.

When the case was finished, one of the FBI agents Clemente worked with took him to lunch and handed him an application to join the bureau.

” ‘They would take me, even though I was a victim?” Clemente asked.

“Of course!” the agent replied.

“It really was the pivotal turning point in my life,” Clemente recalled.

During his FBI career, he worked on child-trafficking cases and white-collar crime. One of the pedophiles he busted was Father Stinner.

Clemente plans to sue the Archdiocese of New York, which ran the summer CYO camp, in Manhattan Supreme Court on Monday under New York’s new Child Victims Act, which created a one year “look back” window for sexual abuse cases past the statute of limitations. He called the law “amazing.”

Investigators believed O’Hara, who died in 2000, had as many as 200 victims. He was first reported in the 1960s in Hewlett, Long Island, when the Boy Scouts created a “perversion file” on O’Hara.

Despite knowing about the accusation, the Archdiocese employed O’Hara at various schools for years, Clemente’s lawyer, Jeff Herman, said.

“It’s shameful that the Archdiocese of New York Catholic schools did not remove O’Hara in 1966, when he was caught the first time,” Herman said.

Clemente urges O’Hara’s other victims to “join us in demanding justice.”

“When it was a deep, dark ugly secret that I couldn’t talk about, it was a deep dark ugly part of me.”

Talking openly about molestation is the only way to stop it and to move on, said Clemente.

“I can tell you from experience, once I went forward and once I confronted him, that’s when I started to turn it around,” he said.