By Joseph Ax

NEW YORK (Reuters) - The domestic partner of an unarmed black man shot dead last fall by a New York City police officer in a dark stairwell filed a wrongful death lawsuit against the city on Thursday on behalf of herself and their young child.

Akai Gurley, 28, was killed on the night of Nov. 20 when Officer Peter Liang, patrolling a Brooklyn housing project with his partner, fired his gun once. The bullet ricocheted off a wall to a stairwell one floor below, where it struck Gurley in the chest.

In February, Liang was charged with second-degree manslaughter and five other counts after prosecutors faulted him for drawing and firing his weapon without cause.

Gurley's domestic partner, Kimberly Ballinger, filed the lawsuit in Brooklyn state court. The complaint names Liang, his partner Shaun Landau, New York City, the police department and the city's housing authority, which operated the project in which Gurley was killed.

A spokesman for the city's law department said, "This incident was tragic. We will review all the claims once we are served with the lawsuit."

Gurley's death added fuel to widespread protests in New York and elsewhere over what critics say is a pattern of lethal police misconduct toward minorities.

His case, however, is different from several other police-related deaths of unarmed black men, such as the fatal shooting of Michael Brown in Ferguson, Illinois.

Liang's lawyer has said he accidentally fired his weapon, and prosecutors have not accused him of shooting Gurley deliberately. Liang has pleaded not guilty.

"We don't believe that Officer Liang intended to kill Mr. Gurley, but he had his finger on the trigger and he fired the gun," Brooklyn District Attorney Kenneth Thompson said at a press conference announcing the charges.

Liang's indictment came after grand juries in both Missouri, in the Michael Brown case, and in New York City's Staten Island, in the chokehold death of Eric Garner, declined to charge the officers involved.

The lawsuit claims Liang acted "negligently and recklessly" and that the two officers failed to summon medical help promptly for Gurley. The suit also faults the housing authority for failing to light the stairwell properly, contributing to the shooting.

It does not seek specific damages, though Ballinger previously filed a $50 million notice of claim in January.

(Editing by Frank McGurty and David Gregorio)