NEW YORK -- An active investigation is underway after a New York City police officer and civilian were shot in Midtown, Manhattan, according to police sources. The shooting happened outside 345 Park Ave., which is the building that contains Blackstone and the NFL headquarters.

Multiple casualties as gunman opened fire in the lobby of the midtown Manhattan building on Park Avenue that is home to the Blackstone investment firm and other corporations before moving to other floors.

At least three people, including an off-duty NYPD cop, were shot and killed in an incident in at one of midtown Manhattan's prime locations, according to authorities. It happened early Monday evening,