The NYPD launched an investigation into a body-cam recording that purported to be of a Brooklyn cop giving oral sex to her boss in a squad car while on duty — but it turned out to be a hoax.

Police sources told The Post that an incident took place during a recent midnight tour in East New York’s 75th Precinct.

The officer and her sergeant purportedly started to get frisky in their car, with the woman tucking her body camera into her vest, thinking it was off, the sources said.

All the time, the sources claimed, the officer was unaware that her body camera was capturing crystal-clear audio of the deed. The camera was rolling throughout the action, they said, capturing the blue duo — neither immediately identified by name — that left little to the imagination.

The alleged audio indicated that the female officer was gushing to her lover about the apparent sex act as they basked in the afterglow, according to the sources.

It was later determined that neither audio nor video existed of the alleged incident.

Sources had claimed the recorded rendezvous was uncovered by a precinct superior during a routine review of body-camera footage after their shift ended.

“It’s disgusting and an embarrassment,” fumed one police source, who added that the sergeant should be demoted for fooling around with a subordinate if the erotic audio is as it seems.

“Especially since he is a supervisor and he would do that to his worker.”

It wasn’t immediately clear where the hoax originated, but word of its existence spread like wildfire around the East New York cop shop — and back to brass at 1 Police Plaza.

“These claims are under review,” the NYPD said in a statement, although department insiders said that as of Wednesday afternoon neither of the cops purportedly involved had been interviewed and remain on full duty.

The hoax comes just one week after the NYPD proudly announced that every beat cop, sergeant and lieutenant on the force — some 20,000 Finest — are now equipped with body cams.

“Body-worn cameras enhance the safety and accountability of the dedicated men and women of the NYPD,” Police Commissioner James O’Neill said then.

The department, which had been expanding body-cam usage since 2017, has already hit at least one other X-rated speed bump.

In December 2018, Brooklyn Detective Specialist Raymond Williams, 44, was suspended without pay for grabbing a colleague’s unattended body cam and using it to record a clip of his testicles.