The fatal shooting of an emotionally troubled ex-Marine by cops Wednesday night in Queens -- the first death from police gunfire in 2015 -- is being investigated by a new NYPD firearms discharge unit, officials said Thursday.

Jonathan Efraim, 30, of Jamaica, Queens, was killed by officers after fleeing a Jamaica bar and restaurant where witnesses told police he had fired a shot from a 9-mm handgun, the NYPD said.

Efraim, who investigators said served in the Marine Corps from 2004 to 2007, was pronounced dead at Jamaica Hospital Medical Center on Wednesday night. His family told police he never deployed overseas.

The frenetic sequence of events began at about 8:17 p.m. when a 911 call reported shots fired inside the Hillside Inn at the corner of 168th Street and Hillside Avenue, police said.

When police arrived, they learned Efraim had fled the bar and headed north on 168th Street toward Highland Avenue, officials said. Officers confronted him a short time later at the intersection of the two roadways and shouted "police, don't move!" according to the NYPD.

Efraim then ran east on Highland toward 168th Place. He turned and ran south through a residential neighborhood on 168th Place with officers pursuing on foot, police said. Efraim stopped on the street, turned and fired twice at the officers as they approached, said Chief of Detectives Robert Boyce at a briefing in Manhattan Thursday.

Two uniformed officers fired five shots, striking Efraim twice in the torso, investigators said. The officers were treated at North Shore LIJ Medical Center for tinnitus -- ringing in the ears.

An NYPD unit established earlier this year to probe incidents of police use of deadly force is handling the investigation, said police spokesman Stephen Davis.

Witness statements support officers' account, Davis said.

As of Wednesday, NYPD officers have been involved in five shootings in 2015, compared with four in the same period last year. Efraim is the first fatality, said an NYPD spokeswoman.

It was unclear what led him to open fire inside the Hillside Inn. Police said he had 16 prior arrests and five incidents where officers had to respond to him as an emotionally disturbed person.

In a 2003 call, police said, Efraim drank bleach in a suicide attempt.