Off-Duty Cop Shot and Killed Man During Road Rage Incident, Police Say The victim's family said he was shot in front of two kids.

 -- An off-duty police officer shot and killed a 37-year-old man in front of his girlfriend and two children during a recent road rage incident in Brooklyn, according to police and the victim's family.

The incident happened just after midnight on Monday, when 37-year-old Delrawn Smalls allegedly got into a dispute with an off-duty New York Police Department officer, according to an NYPD spokesperson. Smalls and the off-duty cop, whom the spokesperson declined to identify, were "stopped at a red light" when Smalls then allegedly exited his car, approached the off-duty cop and began to punch the cop "repeatedly in the head through the car window."

The off-duty officer then "discharged his firearm," killing Smalls in front of a woman and two children who were in his vehicle at the time of the incident, the NYPD spokesperson told ABC News today.

Emergency Medical Services responded and pronounced Smalls dead on the scene, police said. The off-duty cop involved in the road rage incident was then transported to a medical center, where he was treated for "contusions to the head."

Smalls had been on his way to see a fireworks show with his girlfriend and the children when the incident occurred, according to Smalls' brother, Victor Dempsey.

"We was told my brother struck an officer, [but] he's not that type of person to strike an officer," Dempsey told ABC-owned station WABC. "He was with his family in a car with a newborn baby."

Roger Wareham, the attorney for Smalls' family, added at a news conference that Smalls was "an unarmed civilian" and the father to "a 5-month-old who was in the car" at the time of the incident.

The NYPD's Force Investigation Division is looking into the incident and the nature of the original traffic dispute. The Office of the New York State Attorney General is investigating the incident as well, according to the office's spokesman Eric Soufer.

"Members of the Attorney General's Special Investigations and Prosecutions Unit are in contact with the NYPD, the victim's family, and community leaders," Soufer told ABC News in a statement today. "SIPU has a search warrant for the officer's car and is actively reviewing the case."

Wareham did not immediately respond to ABC News' requests for additional comment.