The guilt-ridden rapper who confessed to a 17-year-old murder told The Post yesterday he didn’t know his victim had died when he decided to come clean on the cold case.

Trevell Coleman — whose rap name is G-Dep — said cops dropped the bombshell after he went into the 25th Precinct station house Wednesday to admit to the Oct. 19, 1993, shooting of John Henkel.

“I was surprised — for some reason, I really didn’t think that he died,” the bald and bearded Coleman said in a jailhouse interview.

“When they told me, I was like, ‘Oh, I’m not going home after this.’ ”

Manhattan DA spokeswoman Erin Duggan said Coleman, 36, has now been charged with murder in the case. He faces life in prison.

PREVIOUSLY: RAPPER CONFESSES TO MURDER FROM 17 YEARS AGO

The rapper — who signed with Sean Combs’ Bad Boy label in 1999, was dropped a few years later, and last August signed with Famous Records — said his dark secret “weighed on me.”

It got so bad for him, he confessed despite the objections of loved ones.

“I told my mom and my girlfriend that I wanted to confess, and they both told me to leave it in the past,” he said. “[My girlfriend] is pretty peeved.”

Lyvonnia Copeland, 40, the mother of his three kids, declined to comment yesterday.

Coleman said he’s been dogged by drug addiction, and that at the time of the shooting, “I didn’t think about it.”

“That’s just the life I was living back then,” he said. “I started to wonder if all the bad things that happened to me in my life were karma for what I did . . . you start to think ‘My happiness is because of someone else’s sadness.’

“I thought that if I turned myself in, it might give me closure.”

NYPD Commissioner Ray Kelly called Coleman’s motivations “uncertain — maybe he had a pang of conscience,” but said: “We’ll take it any way we can get it.”

Coleman’s criminal record includes nearly 30 arrests, a law-enforcement source said.

“This guy had particularly bad luck with getting caught,” the source said, noting his most recent bust in November for trespassing with drugs on city-housing property.

“I haven’t been living right,” Coleman told The Post. “I always had people around me that were good people, but I was doing the wrong thing.”

Though he said his confession confounds everyone — “People in [jail] don’t understand how you can confess,” he said — to Coleman, it makes perfect sense.

“I’m just trying to get right with God,” he said.

Coleman said his career was just “little shows here and there.”

“The only thing I regret is that I have to leave my kids,” he said.

Family friend Thomas Frederick, 51, said the Harlem-born rapper’s descent had been distressing for a neighborhood that had idolized him.

“He was like a celeb to the community,” he said. “But after his grandmother who raised him died about four years ago, he was heavily into PCP — like he wanted to leave this world.”