A New Jersey police detective has been indicted on a first-degree murder charge in the shooting of another driver in a road-rage incident.

Joseph Walker (WBAL TV)

An Anne Arundel County grand jury returned the indictment Friday against 40-year-old Joseph Walker of Mount Holly in the June 8 death of Joseph Harvey Jr. of Millersville.

The Capital of Annapolis first reported the indictment. Walker will be arraigned Aug. 19.

Authorities say Walker's minivan cut off a car being driven by Harvey. Harvey's passenger told police that Walker pointed a gun at them. The drivers got out on a ramp, and the passenger says he heard shots. Harvey died at a hospital.

Walker's lawyer said shortly after the incident that the detective's wife and children were in the van and Harvey threatened to kill them.