A Bronx charter-school teacher recruited a student to help him score $4,000 worth of marijuana — and he beat the teen senseless when he found out the kid pocketed the cash, police sources said Friday.

Kevin Pope, 48, also stole the teen’s iPhone and wallet and threatened to sexually assault his mother if he didn’t get his money back, the sources said.

“I will kill you if I don’t get my money!” Pope allegedly told the student after pummeling him. “I want my money in a month!”

Pope, a science teacher at the John V. Lindsay Wildcat Academy in Hunts Point, was arrested at the school Friday morning and charged with assault and robbery in the attack a day earlier.

Pope had asked students around the school back in June if they knew a drug dealer — and they put him in touch with the teen, who promised he could score a large stash of drugs from his contact in Manhattan, sources said.

Pope gave the kid $4,000 for the hefty purchase, the sources said.

The unidentified teen told cops he met the dealer near Central Park but was told that the quantity of drugs he was seeking would cost $7,000, sources said.

The student then blew off the transaction and spent the money, according to the sources.

Three months later, shortly after the start of the new school year, Pope found the teen about two blocks away from the Lafayette Avenue building and demanded that the money be returned, sources said.

When the student said it was gone, Pope allegedly socked him in the face multiple times and took his iPhone 6, gold chain and wallet containing the boy’s school ID and two MetroCards.

A source said that Pope “threatened to have him beat up again and have his mother sexually ­assaulted.”

The student needed three surgical staples to close gashes in the back of his head, sources said.

Sources said the incident is on surveillance video.

The student attends Pope’s school, but it’s unclear if the teen was in that teacher’s class.

A Department of Education spokeswoman directed all questions to the charter school, which declined to comment.

Pope was awaiting arraignment at Bronx Criminal Court on Friday night.

Additional reporting by Kenneth Garger