What to Know A 37-year-old man was shot and killed by an off-duty NYPD officer in East New York, Brooklyn early Monday morning.

A traffic dispute led up to the confrontation. Police say the 37-year-old man punched the cop repeatedly.

The officer was taken to an area hospital but is expected to recover. Police are investigating the nature of the road rage fight.

A man was shot and killed by an off-duty NYPD officer early Monday morning during a traffic dispute in Brooklyn, police said.

The off-duty cop shot 37-year-old Delron Dempsey after Dempsey allegedly got out of his car and began punching the officer in the head during the dispute around midnight in East New York, according to police. But family members disagreed with the NYPD's account, saying Dempsey was shot "on impulse" and was defending his brother.

Police said they received a call of an officer in need of assistance shortly after midnight on Sunday. The off-duty officer was driving his 2002 Nissan Altima east on Atlantic Avenue when he got involved in the dispute with Dempsey.

The two men stopped their cars at a red light at Bradford Street when Dempsey got out of his 2016 Kia EX and went up to the officer, who was still seated in his vehicle. Police say Dempsey then punched the officer repeatedly in his head through the car window.

The officer fired his weapon an unknown number of times during the assault, police said, and Dempsey was shot. He died at the scene.

The officer was taken to Jamaica Medical Center with contusions to his head. He is expected to recover.

Dempsey's relatives were at the scene of the shooting Monday morning and they later said that they have hired an attorney.

New York Attorney General Eric Schneiderman says his office is "actively reviewing the case."

Ali Dempsey said his brother lives in Jersey City but grew up in East New York. He said Delron was visiting his girlfriend, their newborn baby and her two teenagers.

He said witnesses said the officer shot "on impulse." He also defended his brother, saying that he left his car because he didn't want to argue in front of his family.

"The only reason he got out of the car was because the family was in the car. He was concerned. He wanted to question the guy, like, what's your angle?" Dempsey said. "And that was his angle... he killed him."

Ali Dempsey said he's a lifelong resident of the neighborhood and has never experienced anything like this before.

"It's very disturbing. I've never been through none of this in my whole life," he said.

Dempsey's girlfriend and kids were taken to a police station.

Law enforcement sources told NBC 4 New York that the officer was assigned to the 79th Precinct and was a three-year veteran of the force. He had no prior disciplinary proceedings.

Dempsey had 19 prior arrests, the sources said.

A significant stretch of Atlantic Avenue was closed off to traffic early Monday morning as the NYPD's Force Investigation Division investigated the shooting. Stores on the surrounding streets were also closed.

Detectives are trying to figure out the nature of the traffic dispute and how it escalated.