Authorities quickly determined that a former employee of PSE&G, identified as Gary T. Curtis, 58, of Washington, had approached Heller in the parking lot and shot him outside his vehicle, the prosecutor's office said.

Detectives were able to track Curtis down hours later to a parking lot area in Bridgewater Township, where they found him with a self-inflicted gunshot wound, it said. Curtis, who was in possession of a firearm at the time, was pronounced dead shortly after.

Detectives are still working to establish a motive in the incident, the prosecutor's office said.

Heller's death comes a week after Eunice Dwumfour, a fellow Republican who had represented Sayreville, was found fatally shot in her vehicle near her home. Police have yet to identify a potential suspect or motive in her death.

Sayreville is around 55 miles east of Milford.