PENN HILLS, Pa. - A parolee wearing an electronic ankle bracelet fatally shot a man at his home over a $500 drug debt, then walked outside and opened fire on a patrol car, killing an officer awaiting backup, authorities said.

Penn Hills police Officer Michael Crawshaw, 32, was the first to respond to a 911 call made around 8:20 p.m. Sunday. Crawshaw was advised to wait in his patrol car because of past problems reported at the home and because dispatchers heard shots over the phone, Penn Hills Chief Howard Burton said.

Ronald Robinson, 32, opened fire with an assault rifle as he approached the car, Allegheny County Police Superintendent Charles Moffatt said yesterday.

"He didn't go rushing in by himself; he wasn't [trying to be] a hero," Burton said of Crawshaw.

Robinson confessed to killing both men and told police he threw two guns in the nearby woods as he ran from the crime scene, according to a criminal complaint obtained at Robinson's arraignment. Police yesterday found a 7.62 mm Norenko MAK 90 assault rifle and a 9mm Ruger handgun in the woods, the complaint said.

The officer's weapon was removed from his holster, showing that he might have been able to draw his pistol and fire a shot, Moffatt said. Police were still investigating.

Robinson fired at least nine shots at the officer, Moffatt said. An autopsy determined two shots hit Crawshaw in the left arm and a fatal shot hit him in the head, near his left eye, according to the complaint. The man in the house, Danyal Morton, 40, died of several gunshot wounds.