A former Philadelphia school police officer — who had moonlighted as a security guard for big-name rappers — pleaded guilty Thursday to felony charges of sexually abusing two boys.

Howard Rubin, 53, who had worked at Multicultural Academy Charter School until his termination in 2014, was arrested last year. In addition to the sexual assault allegations, he was charged with making violent threats against people who had come forward with incriminating information.

Rubin pleaded guilty Thursday to two counts of involuntary deviate sexual intercourse, one count of corruption of minors, and one count of false incrimination. His sentencing is scheduled for January.

Jane Roh, a spokesperson for the Philadelphia District Attorney’s Office, said the two most serious charges date to 2013, when Rubin sexually assaulted boys who were 12 and 15 years old.

Roh said Rubin met the victims while doing security work at a boys’ dance group. He was not charged with abusing any students at the Hunting Park charter school where he worked. But Roh said her office believes there may be additional victims and is asking them to contact the office’s special investigations unit at DAO_SIU@phila.gov or 215-686-9608.

» READ MORE: Ex-Philly school cop facing charges of child sex abuse

“To those who might have been victimized by this person and have yet to come forward: Please know that you should not feel shame or fear,” District Attorney Larry Krasner said in a statement. “Come forward, tell us what you know, and help us hold this man responsible for any additional crimes he has committed. We will do everything in our power to protect your privacy and safety, just as we have done for the two victims for whom justice was secured today.”

In addition to working as a school police officer, Rubin has provided security for major rappers and other recording artists, including The Notorious B.I.G., who Rubin claimed gave him the nickname “the Philly Hip Hop Cop.”

“With my Napoleon attitude, I would go in, set up security, make sure everything was calm, cool and collected, and I just played my part,” Rubin, a Northeast High grad who is 5-feet tall, told JUMP magazine in 2013. “They had somebody they could trust. Somebody they respected. And someone who wouldn’t disrespect them or what they were doing.”

Rubin’s attorney, Jules Szanto, declined to comment Thursday on the guilty plea.