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CHESTER COUNTY, Pa. (CBS) — The Chester County District Attorney’s Office says the three Pennsylvania State Police troopers who fired their weapons at Bruce Rogal–the man who shot and killed his parents at their retirement home–were justified. In a report released on Wednesday, investigators found that the discharging of their weapons was a “lawful use of force” following the incident that provoked an hours-long manhunt on Sept. 19.

Rogal, 59, had also attempted to shoot his ex-wife on that same day, police say. He crashed his vehicle into his ex-wife’s house after a police chase and was still armed while he sat in his car when troopers arrived on the scene.

Police say there was a shootout, and Rogal died. Officials say Rogal committed suicide during this confrontation.

The exact motive of Rogal’s action that day in September remain unclear. However, officials say that he was newly divorced from his ex-wife, was unemployed and had a girlfriend outside of his marriage for the last decade.

Chester County District Attorney Tom Hogan says his ex-wife took out a restraining order on him that had recently expired.

“Which of these things, which grudge set him off: the divorce decree, the argument with his wife, the eviction notice, the argument with the parents, we don’t know,” explained Hogan. “It was one of those things all coming to a head at the same time. The only person that could’ve told us is dead now.”

Police found hundreds of rounds of ammunition in Rogal’s house. Two of his guns are still missing.