The Maine man who police say confessed to killing his parents and their two friends before going on a shooting rampage on a nearby interstate had been released from prison just days prior – when he’d been picked up by his mother.

Joseph Eaton, 34, appeared briefly in court on Thursday morning and faces four murder charges, with more charges pending. Police arrested him shortly after discovering the bodies of his parents and their friends in a home near Portland on Tuesday morning.

As police searched for Eton on Tuesday, he fled in his parents’ rental car and started shooting at passing vehicles, injuring three members of an area family who were driving past.

The shooting spree stunned Mainers, and Mike Sauschuck, commissioner of Maine Public Safety, called the shootings “an attack on the soul of our state.” It’s one of the worst incidents of violence in Maine history, police said.

Killed in the attack were Cynthia Eaton, 63, and her husband, David, 65, a Navy veteran, and friends Patricia and Robert Eger. The Eatons were staying with the Egans while they picked up their son from prison. Their bodies were discovered Tuesday morning by Patricia Eagan’s sister who grew worried when no one answered the phone, police said.

The three people injured in the interstate shooting were Sean Halsey, 51, and his children Justin Halsey, 29, and Paige Halsey, 25. Police on Wednesday said Eaton confessed after being arrested.

Shooting in Maine on 295:Man fired on motorists after killing 4, including his parents

What do court records reveal?

The Eatons, who lived in Kansas, had gone to Maine to pick up their son, who was released from prison on April 14 after serving a 2015 sentence for domestic violence. Cynthia Eaton met her son at the Maine Correctional Facility in Windham, according to the Maine State Police.