When a suspended Officer Dean confronts Ricky on the stairs at the police station, the position of Ricky's tie keeps changing - at one point being over his left shoulder in a shot from behind him.
When Dean goes back to the garage after being shown up by Leon in front of the crowd, he turns on a hanging light by the car that was not there in all the previous shots of the garage.
When Dean looks out of the window in Ricky's apartment and sees him down on the street, the shot is faked as the sheer curtains Dean is looking through move with the camera as it tracks Ricky walking.
A moving shadow of the boom microphone is visible about 4 minutes in, on the wall of a building in a street scene with two cops and three juveniles.