The death of the unarmed man shot by a probationary NYPD officer in a Brooklyn stairwell last week, has been ruled a homicide by the medical examiners office

Akai Gurley was shot and killed in a stairwell at the Louis H. Pink Houses in East New York late Thursday by officer Peter Liang, who was assigned to the public housing complex as part of a violence reduction overtime detail.

Police Commissioner Bill Bratton has called the shooting an accident and said Gurley was a “total innocent.”

Liang and his partner, both of whom have less than 18 months on the force, were conducting a floor-by-floor sweep of the building and had gone to the roof when they noticed there were no lights in the stairwell leading up to it. Given the location and lack of light, Liang drew his weapon and a flashlight for safety reasons, police have said. The other officer kept his service weapon holstered.

As the officers were entering the eighth-floor landing, Gurley emerged on the seventh-floor landing. He heard a noise and turned to look up at the two officers a floor above him, a law enforcement source said. Then Liang, who had his gun in his left hand and his flashlight in his right, fired accidentally, hitting Gurley 11 feet below him, according to Bratton.

Gurley was shot in the chest. He stumbled down to his girlfriend, who was by that point on the fifth floor, and she tried to administer first aid, authorities said. Liang and his partner found the couple on the fifth floor; 911 had already been called. Gurley was pronounced dead at a hospital.

The medical examiner’s ruling came shortly after Brooklyn District Attorney Kenneth Thompson announced he would launch an investigation into Gurley’s death. Thompson met with community leaders on Sunday, a day after more than 250 people marched in protest outside Liang’s 75th Precinct, chanting and holding signs calling for justice.

The NYPD’s Internal Affairs Bureau is investigating along with the district attorney’s office. Liang has been placed on modified duty pending the outcome of the investigation.

The police union has called for a thorough investigation. Neither the union nor the NYPD could immediately be reached for comment on the medical examiner’s ruling.

-Tamara El (@_SheWise_)