Three Pennsylvania state troopers followed the law when they fired their guns at Bruce Rogal, the 59-year-old Glenmoore man who killed his parents in September during a rampage and then fatally shot himself, the Chester County District Attorney's Office said Wednesday.

The troopers confronted Rogal after he crashed his minivan into his ex-wife's West Bradford home about 1 a.m. on Sept. 20, prosecutors said. District Attorney Tom Hogan said in a statement that "the firearm discharges constituted a lawful use of force" by the troopers. Hogan's office conducted an independent investigation of the discharges.

The night before, Rogal shot his parents, Nancy, 87, and William, 89, at the Bellingham retirement community in East Goshen. Hours earlier, he attempted to shoot his ex-wife, Catherine Christian, outside her home. Her divorce from him had been finalized the day before and she had a prior protection-from-abuse order against Rogal that expired last year.

The troopers located Rogal's silver Honda Odyssey based on a tip and followed it until the crash. They heard gunfire and discharged their weapons, but Rogal had already killed himself.