From Huffington Post:
The victim, Akai Gurley, (pictured above) had spent the evening at his girlfriend’s apartment inside the Louis Pink housing projects. The couple left the seventh floor apartment around 11:15 p.m. and tried to take an elevator down to the bottom floor. When the elevator wouldn’t work, they entered the stairwell.
Two officers, meanwhile, were conducting a vertical patrol -- also known as a top to bottom patrol -- inside the building. Upon entering the "dark" stairwell on the eighth floor, Officer Peter Liang drew his gun and flashlight as a safety precaution. That's when Gurley and his girlfriend -- identified by the New York Daily News as Melissa Butler -- also entered the stairwell.
At that moment, Liang fired one round from the eighth floor landing. Gurley, who was on the seventh floor landing, was struck in the chest.
The wounded man and his girlfriend then ran down the stairs before Gurley collapsed on the fifth floor. Under instructions from a 911 operator, Butler then tried to administer first aid. Gurley was transported to Brookdale Hospital, where he was pronounced dead on arrival.
New York City Police Commissioner William Bratton said that according to a preliminary investigation, "it appears this may have been an accidental discharge." Gurley "was not engaged in any criminal activity of any type. He didn’t do nothing wrong. He was just standing there and they shot him. He was an innocent man.
Liang and the other officer were taken to the hospital to be treated for tinnitus, which is a ringing noise inside the ears, often caused by gunfire.
Brooklyn District Attorney Ken Thompson is investigating the incident. NYPD Internal Affairs is also investigating.