The sergeant who serves as the NYPD school liaison in south Brooklyn has been stripped of his gun and badge after refusing to speak to investigators from the FBI’s corruption unit without a lawyer, sources told The Post.

FBI agents showed up at Erez Levy’s door last Friday. Levy, a 15-year veteran who was assigned to Patrol Borough Brooklyn South, wasn’t home at the time, but his girlfriend passed on their message, sources said.

Levy contacted a union lawyer who reached out to the feds on his behalf. Ten minutes later, the NYPD’s Internal Affairs Bureau ordered Levy to come in, at which point they placed him on modified duty, sources said.

On Monday, he reported to police headquarters, where he was issued a modified ID card.

NYPD spokesman J. Peter Donald would say only that Levy “was modified for the good of the department.”

Levy, who made $122,974 in 2015, was disciplined amid a wide-ranging federal probe into NYPD corruption.

“As far as we can determine, Sgt. Levy’s modification has absolutely nothing to do with the federal probe into the NYPD,” said Andrew Quinn, lawyer for the Sergeants’ Benevolent Association.