Thursday morning, law enforcement personnel are investigating after a shooting killed three police officers and wounded two others in Southcentral Pennsylvania the day before.

Here’s what is known so far:

York County officers from as-yet unidentified departments were following up on a domestic-related investigation that began Tuesday. They went to a property on Haar Road in North Codorus Township, in southern York County, when they were fired upon. The shooter, wearing camouflage, appeared to be lying in wait in a cornfield when officers arrived, sources said.

Five officers were hit. Three were killed, 2 seriously injured. The two injured officers were in critical but stable condition at York Hospital, authorities said Wednesday night.

Police killed the shooter, state police said at a news conference.

Gov. Josh Shapiro condemned the violence at a news conference. “This is an absolutely tragic and devastating day for York County and the entire commonwealth of Pennsylvania,” he said.

“We need to help the people who think that picking up a gun, picking up a weapon, is the answer to resolving disputes,” Shapiro said. “We need to do better when it comes to mental health, and dealing with those in need.”

Hours after the violence, community members held American flags and saluted as police and emergency vehicles formed a procession to the coroner’s office.

U.S. Attorney General Pamela Bondi called the violence against police “a scourge on our society.” Federal agencies were on hand to help with the investigation.

Police departments, lawmakers and others across the region expressed condolences on social media. People were leaving flowers at the headquarters of the Northern York Regional Police Department. State flags were ordered to fly at half-staff.

The investigation into the shooting will cover multiple locations in York County, state police said. Authorities did not on Wednesday identify the shooter, the officers or which police departments they belonged to, or describe how they were shot, citing the investigation.

It was one of the deadliest days for Pennsylvania police this century. In 2009, three Pittsburgh officers responding to a domestic disturbance were ambushed and shot to death by a man in a bulletproof vest.

Another officer in York County was killed in February, after a man armed with a pistol and zip ties entered a hospital’s intensive care unit and took staff members hostage. A shootout left both the man and an officer, Andrew Duarte, dead.