The Brooklyn district attorney’s office announced on Wednesday that it would not seek prison time for the former New York City police officer convicted last month in the fatal shooting of an unarmed man in a housing project in East New York.

In a statement, the district attorney, Ken Thompson, said the case was about “justice and not about revenge,” and urged that the former officer, Peter Liang, receive five years of probation, including six months of home confinement, when he is sentenced next month.

Mr. Liang, 28, who was convicted of second-degree manslaughter, could be sentenced to as much as 15 years in prison.

“Mr. Liang has no prior criminal history and poses no future threat to public safety,” Mr. Thompson said. “Because his incarceration is not necessary to protect the public, and due to the unique circumstances of this case, a prison sentence is not warranted.”