The gunman who killed three Pennsylvania police officers and wounded two others was waiting inside the farmhouse home of his ex-girlfriend and her mother when police arrived on the scene Wednesday afternoon.

The two women had left the home for someplace safer on Tuesday when the killer, identified as 24-year-old Matthew J. Ruth, was seen outside the home wearing camouflage, carrying an AR-style rifle, and peering into windows with binoculars, as stated by York County District Attorney Tim Barker during a Thursday news conference.

Northern York County Regional Police Department officers Det. Sgt. Cody Becker, Det. Isaiah Emenheiser, and Det. Mark Baker lost their lives in the incident on Wednesday afternoon, along with the women’s family dog, who was discovered shot dead in the basement.

Another NYCRPD detective and a York County sheriff’s deputy were critically wounded.

The ex-girlfriend’s mother called police at about 11:30 p.m. Tuesday night to report that Ruth was on her North Codorus farm, Barker said.

“There was a call that came in from the mother of (Ruth’s) ex-girlfriend that the actor was spotted on her property with binoculars, looking through the residence, looking through a window,” Barker described. “She could see him through a trail camera that was standing in her driveway.”

She informed the officers arriving at the scene that Ruth might have reached the property in a black truck parked around the corner, and an officer discovered the unoccupied black pickup truck parked nearby, but the suspect was not found.

“Officers went back to the residence and spoke with both the ex-girlfriend of the actor and the mother of the actor, and the ex-girlfriend of the actor had advised that on 8/20 of 2025, an unknown person set her pickup truck on fire while it sat in her driveway,” Barker said. “She advised that at the time, she suspected that it was her ex-boyfriend who was a culprit, but she wasn’t sure. So she requested that the matter not be investigated further.”

Officers were shown the trail camera photo of Ruth, which showed him completely dressed in camouflage with an AR-15 style rifle slung across his chest. The ex-girlfriend said she’d dated him for a short period of time and that he had never been to her home nor been invited there.

A family friend later told WHP that the two had dated for about two weeks.

Officers were unable to locate Ruth, however, and obtained a warrant for Ruth’s arrest — on charges of stalking loitering and prowling at nighttime, and criminal trespassing — and a search warrant for his home the next day. Becker, Baker, Emenheiser and two other detectives executed the warrant just after 12 p.m., speaking with his family and then leaving.

The five detectives then went back to the farm, arriving just after 2 p.m., accompanied by a York County deputy with a drone. The detectives searched outbuildings on the farm while the drone checked the fields.

Emenheiser, Baker, Decker, and one of the other detectives went to the front door of a farmhouse at about 2:08 p.m. and found it unlocked. Because the detectives remembered that the ex-girlfriend and her mother had locked the door when they left, they decided to enter the home.

“Upon immediately opening the door, the actor repeatedly fired at the officers with multiple rounds from an AR-15 styled rifle with a suppressor,” Barker said.

Baker, Decker, and Emenheiser were immediately hit.

“All four detectives went down,” Barker said. “The actor then proceeded to turn his attention to the deputy sheriff. The deputy sheriff, and the other Northern York County Regional detective began to position themselves to return fire.”

The detective opened fire at Ruth, who shot the deputy and the deputy’s vehicle. The deputy also opened fire on the gunman. Ruth went toward the roadway, where police vehicles were parked, after the deputy was hit, and both the deputy and the detective shot at him. Barker said “there was a final exchange of gunfire” at the roadway,” and Ruth was shot and killed.

The entire shootout lasted for about 16 seconds, he said.

Afterward, investigators found the family dog shot dead in the basement of the home.

Barker said that if the ex-girlfriend and her mother had arrived instead of police, “they would have been killed immediately.”

“Numerous other search warrants have been executed,” the DA said. “Other things are being analyzed. There is one motive, though, that is clear for everything, and that is the hateful scourge of domestic violence.”

Previous reporting on the incident indicated that two York County sheriff’s deputies were wounded and that the killer opened fire from a cornfield, but Barker corrected that erroneous reporting on Thursday.