Pennsylvania cop killer Matthew Ruth fired at officers the moment they entered his stalking victim’s house, which was empty save for a dead dog

The gunman who killed three Pennsylvania police officers and hurt two more ambushed the cops the moment they opened the front door to the house of his stalking victim, which was empty except for the corpse of the family dog he had killed inside, officials revealed Thursday.

Det. Sgt. Cody Becker, Det. Mark Baker and Det. Isaiah Emenheiser, of the Northern York County Regional police force, were identified as the victims of Matthew Ruth, killed when they opened the unlocked front door to the home during a domestic violence probe Wednesday, said York County District Attorney Timothy Barker.

Police had visited the same home, where Ruth’s ex-girlfriend lived, the night before after a report of the gunman lurking outside her house with an AR-15.

Another Northern York officer and a York County Sheriff deputy were also wounded during the barrage, said Barker.

“They arrived at the door … the door was opened and upon immediately opened the door, the actor repeatedly fired at the officers,” he said.

Ruth was later killed during an exchange of gunfire.

A black lab was also found dead inside the home from a single gunshot wound.

The ex-girlfriend and her mother fled the home earlier in the day for their own safety.