New York- A grainy clip from an NYPD surveillance camera showing a man committing suicide in a Bronx housing project wound up on a porn Web site – and investigators want to know how, police said yesterday.

The shocking footage, recorded March 16, shows Paris Lane, 22, embracing a teenage girl as she gets into an elevator, then shoving a gun in his mouth and firing.

Yesterday, investigators from the NYPD’s Internal Affairs Bureau grilled Police Service Area 7 housing cops over the matter.

Lane’s foster mother and the girl on the tape, who said she was “just friends” with the Harlem man, also are looking for answers.

“I thought I was healing until they put this on the Web site, a sleaze Web site,” said Martha Williams, 56, who began caring for Lane after his parents died of AIDS when he was 11.

“That was my baby. I raised him,” she said, surrounded by pictures of Lane, an aspiring rapper who used the name Paradice.

“He had it tough, but he was a good kid,” she added.

There were three closed-circuit cameras in the lobby of 1358 Washington Ave. in the Gouverneur Morris Houses that captured Lane’s final moments.

The tape from one of those cameras was sent to an Atlanta-based Web site that features sexual depravity and violence.

The NYPD’s viper unit is responsible for monitoring cameras recording public housing developments.

The girl, Krystin Simmons, 16, was stunned when her phone began ringing with friends telling her that footage of the tragic last goodbye was being played on the Web.

“I gave him a hug and got into the elevator. When the elevator got to the second floor, I heard the shot,” Krystin said.

“It’s wrong,” she added. “Every night I have to think about this, and it’s hard for me to go to sleep. I lost a friend. It shouldn’t be exploited.”

Paul Ganin, who runs the Web site, said Lane’s suicide was removed after NYPD detectives began asking questions. Ganin claimed he did not know where the image came from – only that it was posted by one of the site’s members who said he had “friends at the scene.”

“I wasn’t even aware of its existence until people started E-mailing me about ‘the Paris suicide video,'” he said. Ganin said he thought they were talking about Paris Hilton, the publicity-loving hotel heiress whose sex video made the Internet rounds last year. He said that once cops told him what the video was about, he took it down and pledged to cooperate.

Still, Ganin could face charges for posting the video, which is the property of the NYPD, said police spokesman Paul Browne.