A rookie police officer shot and killed an unarmed 28-year-old man in an unlit stairwell of a housing project in what New York 's top cop said Friday William Bratton , late Thursday , was shot after entering a stairwell in Staten Island with girlfriend . A rookie police officer `` accidentally discharged '' his weapon , police say . Police Commissioner Ken Thompson calls victim a `` total innocent '' Brooklyn D.A . William Bratton says shooting is `` deeply troubling ''
William Bratton , late Thursday , was shot after entering a stairwell in Staten Island with girlfriend . A rookie police officer `` accidentally discharged '' his weapon , police say . Police Commissioner Ken Thompson calls victim a `` total innocent '' Brooklyn D.A . William Bratton says shooting is `` deeply troubling ''