Two police officers prepared to enter the pitch-black eighth-floor stairwell of a building in a Brooklyn housing project, one of them with his sidearm drawn. At the same time, a man and his girlfriend, frustrated by a long wait for an elevator, entered the seventh-floor stairwell, 14 steps below. In the darkness, a shot rang out from the officer’s gun, and the 28-year-old man below was struck in the chest and, soon after, fell dead.
The shooting, at 11:15 p.m. on Thursday, invited immediate comparison to the fatal shooting of an unarmed man in Ferguson, Mo. But 12 hours later, just after noon on Friday, the New York police commissioner, William J. Bratton, announced that the shooting was accidental and that the victim, Akai Gurley, had done nothing to provoke a confrontation with the officers.
Indeed, as the investigation continued into Friday night, a leading theory described an instance of simple, yet tragic, clumsiness on the part of the officer. Mr. Gurley was not armed, the police said.
The episode promised to bring scrutiny to a longtime police practice of officers drawing their weapons when patrolling stairwells in housing projects.
The shooting occurred in the Louis H. Pink Houses in the East New York neighborhood. The housing project had been the scene of a recent spate of crimes — there have been two robberies and four assaults in the development in the past month, two homicides in the past year, and a shooting in a nearby lobby last Saturday, Mr. Bratton said.
Additional officers, many new to the Police Department, were assigned to patrol the buildings, including the two officers in the stairwell on Thursday night, who were working an overtime tour.
Having just inspected the roof, the officers prepared to conduct what is known as a vertical patrol, an inspection of a building’s staircases, which tend to be a magnet for criminal activity or quality-of-life nuisances.
Both officers took out their flashlights, and one, Peter Liang, 27, a probationary officer with less than 18 months on the job, drew his sidearm, a 9-millimeter semiautomatic.
Officer Liang is left-handed, and he tried to turn the knob of the door that opens to the stairwell with that hand while also holding the gun, according to a high-ranking police official who was familiar with the investigation and who emphasized that the account could change.
It appears that in turning the knob and pushing the door open, Officer Liang rotated the barrel of the gun down and accidentally fired, the official said. He and the other officer both jumped back into the hallway, and Officer Liang shouted something to the effect that he had accidentally fired his weapon, the official said.
Mr. Gurley had spent the past hours getting his hair braided at a friend’s apartment. Neighbors said he had posted photos of himself on an online site for models, featuring his tattoos, his clothing and his muscular frame.
He and his girlfriend, Melissa Butler, waited for an elevator on the seventh floor, but it never came, so they opened the door to the dark stairwell instead. An instant later, the shot was fired. Mr. Gurley and Ms. Butler were probably unaware that the shot came from a police officer’s gun.
“The cop didn’t present himself, he just shot him in the chest,” Janice Butler, Ms. Butler’s sister, said. “They didn’t see their face or nothing.”
Mr. Gurley made it two flights down, to the fifth floor, where he collapsed. Melissa Butler called 911 from a lower floor, the official said.
Officer Liang and his partner came upon Mr. Gurley and called in the injury on the police radio, saying it was the result of an accidental discharge, the official said.
Mr. Gurley was taken to Brookdale Hospital, where he was pronounced dead. Following protocol, Officer Liang was relieved of his gun and his badge pending an investigation.
Commissioner Bratton called Mr. Gurley “a total innocent” and said the shooting was “an unfortunate accident.” The victim was not engaged in any activity other than trying to walk down the stairs, Mr. Bratton said.
Mayor Bill de Blasio was also quick to offer his condolences to Mr. Gurley’s family. “This is a tragedy,” he said.
About 6:45 p.m. on Friday, the mayor, accompanied by his wife, Chirlane McCray, and Mr. Bratton, arrived at the Red Hook East Houses to visit the home of Mr. Gurley’s domestic partner, Kimberly Michelle Ballinger, 25.
They spent a little more than 10 minutes there and left without making any comment.
Earlier, Mr. Bratton said that whether an officer should draw his weapon while on patrol when there was no clear threat was a matter of discretion.
“There’s not a specific prohibition against taking a firearm out,” he said, adding, “As in all cases, an officer would have to justify the circumstances that required him to or resulted in his unholstering his firearm.”
The president of the Patrolmen’s Benevolent Association, Patrick J. Lynch, declined to say anything about the officer, but commented on the conditions of stairwells in projects, including the setting of the shooting.
“The Pink Houses are among the most dangerous projects in the city, and their stairwells are the most dangerous places in the projects,” he said. “Dimly lit stairways and dilapidated conditions create fertile ground for violent crime, while the constant presence of illegal firearms creates a dangerous and highly volatile environment for police officers and residents alike.”
The Brooklyn district attorney, Kenneth P. Thompson, issued a statement that questioned the condition of the lighting in the stairwell.
“Many questions must be answered, including whether, as reported, the lights in the hallway were out for a number of days, and how this tragedy actually occurred,” Mr. Thompson said.
Neighbors said darkened stairwells were nothing new in the Pink Houses. “The staircases from eight down are dark,” said Mattie Dubose, a resident. “If you want to walk in them, you need an escort.”
