Surveillance video exclusively obtained by CBS News New York Investigates shows NYPD officers repeatedly punching a man working at a Brooklyn homeless shelter last February.

Four people were injured Sunday afternoon at a Brooklyn subway stop in what started as officers' attempts to apprehend a man accused of skipping the station turnstile.

Police officials shared more details about the Brownsville, Brooklyn subway station shooting during a Wednesday evening news conference. They said the violence, captured on body-worn cameras and 15 surveillance cameras at the station and on the trains, began when a man accused of fare evasion later charged at police with a knife.