New York - A former police officer convicted in the shooting death of an unarmed man in a darkened stairwell was spared prison time on Tuesday, and a judge reduced his manslaughter conviction to a lesser charge.Peter Liang was sentenced to five years' probation and 800 hours of community service in the 2014 shooting of Akai Gurley, who was walking down a stairway in a public housing complex when the rookie officer fired a bullet into the dark - by accident after being startled, he said. The bullet ricocheted and killed Gurley, 28."Given the defendant's background and how remorseful he is, it would not be necessary to incarcerate the defendant to have a just sentence in this case," Brooklyn state Supreme Court Justice Danny Chun said in sentencing Liang, also 28.A jury had convicted him in February of a manslaughter charge carrying up to 15 years in prison. But Chun on Tuesday reduced the offence to criminally negligent homicide, which carries up to four years in prison.Brooklyn prosecutors recommended Liang serve no time, based on his record and the circumstances of the trial. They suggested five years of probation, six months of home confinement and 500 hours of community service.Some members of Gurley's family said they felt betrayed by Thompson's recommendation and had hoped Chun would sentence Liang to prison anyway.The shooting happened in a year of debate nationwide about police killings of black men. Activists have looked to Liang's trial as a counterweight to cases in which grand juries have declined to indict officers, including the cases of Michael Brown in Missouri and Eric Garner in New York. Like Gurley, Brown and Garner were black and unarmed. Liang is Chinese-American.Brooklyn District Attorney Kenneth Thompson cautioned that Liang's case shouldn't be commingled with others. But relatives of other New Yorkers killed in police encounters had joined Gurley's family outside court during the trial to call for police accountability.Meanwhile, Liang's supporters have said he has been made a scapegoat for past injustices.