Deadly Manhattan office shooting claims four lives

A New York City police officer and three other victims are dead following a shooting at a Manhattan office building Monday evening.

(CNN)- A New York City police officer and three other victims are dead following a shooting at a Manhattan office building Monday evening. Another man remains in critical condition, according to authorities.

Officials say the suspected gunman died from what appears to be a self-inflicted gunshot wound. The fallen officer has been identified as 36-year-old Didarul Islam, who was working security at the Park Avenue high-rise when the shooting occurred.

“Officer Islam was married with two young boys, and his wife is pregnant with their third child,” said NYPD Commissioner Jessica Tisch.

The building where the shooting happened houses the offices of several major organizations, including the NFL and investment firm Blackstone. Authorities say the gunman walked into the building with an M-4 assault rifle, opening fire first in the lobby and later on the 33rd floor.

“He wasn’t there looking to kill people at random,” said former NYPD Chief Kenneth Corey. “He could have done that right on the streets of Midtown Manhattan with that rifle and taken a lot more lives.”

Police have identified the suspect as a 27-year-old man from Las Vegas with a history of mental health issues. They say he had a concealed carry license and no significant criminal record. His motive remains unknown as local and federal agencies continue to investigate.