SEE IT: NYPD officer kneels on man’s head, waves gun at onlookers during Brooklyn arrest

An NYPD cop with his gun drawn knelt on a man’s head while a concerned witness begged the officer to “calm down,” video obtained by the Daily News shows.

The footage is believed to have been recorded last week on Dean St. near 6th Ave. in Prospect Heights, said sources.

The video shows the plainclothes...