A former Boy Scout pleaded guilty Wednesday to killing his troop leader, who he claimed had raped him over many years.

In a tense and emotional courtroom in Newton, New Jersey, Clark Fredericks admitted to killing former Boy Scout leader and Sussex sheriff's officer Dennis Pegg three years ago.

"From the time I was 8 years old until I was 12, I was sexually assaulted and raped by Dennis Pegg," said Fredericks.

He said he never told anyone about the rapes even as, he claimed, Pegg also raped his best friend Jeff. Jeff committed suicide in 1983, Fredericks said.

Fredericks graduated high school, still keeping the secret from his parents.

"Dennis Pegg controlled me by torturing and killing animals in front of me, saying he would do the same to me if I told anyone about our secret," he said.

Fredericks said he felt that Pegg, as a cop, was untouchable.

But in 2012, he watched the sexual abuse trial of Penn State coach Jerry Sandusky and then his conviction on June 11. "The next day, June 12, my shell cracked," he said.

Fredericks said he got drunk, snorted cocaine, and with friend Bob Reynolds -- who police arrested as an accomplice -- went to Pegg's Stillwater home with a hunting knife Pegg had given him back in scouting.

"I started stabbing Dennis," Fredericks said in court. "I said, 'How does it feel raping little kids now. It's not so fun raping little kids now, is it?' At the end I slit his throat."

Family and friends of Fredericks wept almost nonstop as he spoke. And then as he got up to leave, applause broke out in the courtroom, something the prosecutor said he'd never seen before.

One of those crying and applauding was Rose Funari, who said her own brother was a victim of Pegg's.

"If someone was to hurt my child, I'll be honest with you, there would be no judge, no jury," she said.

Family and friends said past accusations by others against Pegg were ignored. Prosecutor Francis Koch said there was simply was not sufficient evidence. Either way, the prosecutor would not justify an eye for an eye.

Despite the savage nature of the killing, even the prosecutor agreed to accept the claim of passion provocation, which means a maximum of 5 to 10 years when he is sentenced in August.

"Passion provocation could not be disapproved beyond a reasonable doubt," said Koch.