A crook with a long rap sheet escaped police custody early Saturday in Brooklyn, making a desperate bid for freedom while still handcuffed, authorities said.

Tyrone Johnson, 24, of East New York, was pulled over for failing to signal just before 4:30 a.m. at Osborn Street and Lott Avenue in Brownsville, police said. Cops then discovered that he had an outstanding bench warrant for a drug charge, and arrested him.

On the way to the 73rd Precinct station house, Johnson made a run for it, possibly escaping through the cruiser’s rear window, cops said. It wasn’t immediately clear whether he broke the window, or it was already open.

Still cuffed, he fled south on Thomas Boyland Street from Livonia Avenue, police said.

Johnson is about 5-foot-9 and 150 pounds, with a dark complexion, brown eyes and black hair. He was last seen wearing a camouflage jacket and dark colored jeans.

He has 16 prior arrests for offenses including grand larceny, robbery, gun possession and criminal mischief, cops said.