A rookie police officer has pleaded not guilty to manslaughter and official misconduct, among other charges, after gunning down a man in a dark stairwell of a public housing complex in Brooklyn.

Officer Peter Liang appeared in a courtroom on Wednesday. His attorney is claiming that the shooting was an accident. Liang was released without bail, according to an Associated Press report.

Liang is accused of shooting to death 28-year-old Akai Gurley on Nov. 20 while he was visiting a public housing complex in an East New York neighborhood to braid his hair. Liang and his partner were patrolling nearby as reports of violent crime in the area had been high. Liang had been 18 months into the job at that point.

Liang descended onto an eighth-floor landing of the stairwell with his gun drawn, and then Gurley opened the door to the seventh-floor landing after getting tired of waiting for the elevator, according to prosecutors.

Liang, who was also holding a flashlight in his right hand, allegedly fired a shot that ricocheted and hit Gurley in the chest. Gurley went down two flights of stairs and then suddenly collapsed.

Liang and his partner then retreated to the eighth floor and argued about whether to report that a weapon had been discharged rather than immediately seeking to assist the victim, according to prosecutors.

His partner recalled Liang saying that it was an accident and that he was going to get fired.

Prosecutors say that protocol requires officers to keep their weapons pointed down and with a finger off the trigger if there is no clear threat.