Officials say a man carrying a rifle killed four people at a New York City office tower. The shooting took place Monday afternoon at a midtown Manhattan office building that houses finance companies and the NFL headquarters. The victims include an off-duty New York City police officer. The gunman also wounded a fifth person before taking his own life. He was identified as a Las Vegas resident. Four other people got minor injuries attempting to flee the scene. Police Commissioner Jessica Tisch said the gunman had a "documented mental health history." The motive is still unknown.