Authorities say 24-year-old Matthew Ruth fatally shot three Pennsylvania police officers and wounded two others on Sept. 17.

The shooter was stationed inside the house and immediately began firing with an AR-15-style rifle, Barker said.

Investigators also discovered a black lab shot dead in the basement of the house that belonged to the ex-girlfriend of the shooter.

[The ex girlfriend] also told investigators that she believed Ruth had set her pick-up truck on fire while it was sitting in the home’s driveway in August, according to an affidavit.