New York City police Officer Peter Liang was convicted of manslaughter Thursday in the 2014 shooting death of an unarmed black man in a darkened Brooklyn public housing project stairwell.

Liangs single gunshot killed Akai Gurley , 28, who was walking down the stairs on Nov. 20, 2014.

NYPD said after the jurys verdict that Liang had been fired from the department. He faces up to 15 years in prison when he is sentenced on April 14.

Liang said he drew his pistol as he and his partner patrolled the darkened 8th floor stairwell of the Louis H. Pink Houses in Brooklyn. He said he flinched when he was startled by a noise, which he said caused the gun to fire.

The bullet ricocheted off of the stairwell wall and struck Gurley, who was on the seventh floor. Gurley, who was unarmed, died from a wound in his chest.

Liang tearfully recounted the shooting in court, claiming his finger was never on the trigger.

I was panicking. I was in shock, in disbelief that someone was actually hit, he told jurors.

Prosecution evidence contradicted the claim and showed pressure had to have been applied to the trigger in order for the weapon to fire. To test this notion, the judge allowed each of the 12 jurors to take turns pulling the trigger of Liangs handgun.

Liang and his partner testified they didnt realize anyone had been shot for several minutes and said they didnt try to perform CPR on Gurley because they felt untrained.

Gurleys family was unmoved by the rookies tears.

Peter Liang, my son was no accident, Sylvia Palmer, the victims mother, said Monday. You murdered my son. I need justice for my son. I need a conviction of Peter Liang.

Mayor Bill de Blasio called Gurleys death a tragedy.

The jury has now spoken, and we respect its decision, de Blasio said. We hope todays outcome brings some closure to the Gurley family after this painful event.

Patrick J. Lynch, head of the citys police union, criticized the jury for what he called an absolutely wrong decision.

This was a terrible and tragic accident and not a crime, said Lynch, the Police Benevolent Association president. This bad verdict will have a chilling effect on police officers across the city because it criminalizes a tragic accident.

Convictions of police officers involved in shootings are exceedingly rare. The last time an NYPD officer was convicted in a shooting death of a civilian was 2005, when Bryan Conroy was convicted of criminally negligent homicide in the killing of Ousman Zongo, an unarmed African immigrant.

Sanctions for the use of lethal force are also rare. A 2014 New York Daily News investigation found that out of the 179 people killed by on-duty police officers during 15 years, just three of those deaths resulted in indictments.

This article has been updated to include Lynchs comment.