WEST BATH (AP) — A Maine man who police say confessed to shooting seven people — killing four of them, including his parents — after being released from prison was due to appear before a judge Thursday.

Police have not discussed what might have been a motive behind the shootings on a rural property in Bowdoin and then along a busy interstate highway in Yarmouth, about 12 miles from Maine's largest city, Portland.

The suspect, Joseph Eaton, has been jailed since his arrest Tuesday at a chaotic scene along Interstate 295, where traffic backed up as heavily armed law enforcement searched the area.

Eaton, 34, had been released four days before the shootings from the Maine Correctional Center in Windham. Police say his mother picked up from prison April 14 after he completed a sentence for aggravated assault.

The latest in a string of mass shootings in the United States began in the small town of Bowdoin, where four people were killed Tuesday, with three bodies discovered in a home and one in a barn, police said. The victims were identified as Joseph Eaton's parents, Cynthia Eaton, 62, and David Eaton, 66, along with their friends, homeowners Robert Eger, 72, and Patricia Eger, 62, police said.

Police say Eaton told them he began firing on several cars along I-295 soon thereafter because he thought he was being followed by police. Bullets struck a family in one of the vehicles: Sean Halsey, 51; Justin Halsey, 29; and Paige Halsey, 25, police said. Paige Halsey was critically injured, police said.

Police say Eaton was briefly evaluated at a hospital but was not injured in his arrest.

Eaton is charged with four counts of murder but has not yet been charged in the highway shootings.

A man an believed to be Joseph Eaton posted on social media on the day he was released from prison: "It's finally over. There are so many people I can't wait to see."

Days later, the man's demeanor had changed as he posted an anguished live video criticizing people who he said are Christian but don't give people a second chance.