WEST BATH — A man who told police he killed his parents and their friends and shot at motorists on a busy interstate highway might try to show he was insane, based on pleas he entered Friday.

The 34-year-old ex-convict Joseph Eaton entered pleas of both not guilty and not criminally responsible, leaving him the option of an insanity defense against charges including four counts of murder.

"At this point we are preserving the ability to move forward with the so-called insanity defense. Once we have more forensic information, full discovery, and are able to view the case as a whole, we will then decide how to proceed," Andrew Wright, one of his attorneys, told The Associated Press before the hearing in West Bath.

Law enforcement officials say Eaton confessed to the killings at a property in rural Bowdoin, and to wounding three people while shooting at vehicles on Interstate 295 in Yarmouth.

Eaton has been jailed since his arrest on April 18 near the chaotic scene along the highway, where traffic backed up as heavily armed law enforcement searched the area.

The bodies were found in Bowdoin that morning, days after Eaton's mother picked him up at a prison in Maine where he had done time for violating probation on an aggravated assault conviction, the latest in a long criminal history.

Eaton's parents, Cynthia Eaton, 62, and David Eaton, 66, were killed along with their longtime friends, Bowdoin homeowners Robert Eger, 72, and Patti Eger, 62, officials said. Also killed was the family dog, resulting in a cruelty to animal charge. He was also charged with stealing weapons.

Police still don't know Eaton's motive for the slayings. A criminal affidavit stated that an unsigned note found at the scene mentioned "someone being freed of pain and that the writer of the note wanted a new life."

Eaton sat in silence during the hearing Friday afternoon, wearing glasses, a full beard and a prison jumpsuit while his attorney, Andrew Wright, entered the plea, “Not guilty, not criminally responsible,” on his behalf. Eaton only spoke twice, saying “Yes, sir,” when asked twice if he understood the charges against him.

Justice Daniel Billings ordered Eaton held without bail on the murder counts and set bail at $250,000 for all other charges. 

A total of 24 people, including Sean Halsey and members of the Eger family, were in the courtroom for Friday’s hearing. When Eaton’s plea was entered in, some members exhaled audibly, while others wept. 

After the hearing, Patricia Eger’s brother, Peter G. DeRaps, stormed into the lobby shouting expletives. While other family members filed out of the building Patricia Eger’s sister, Denise Gilbert, sat on a bench in the lobby to compose herself, dabbing her eyes with a tissue.

“I just miss her,” she said of her sister. “It’s so senseless. My family’s lost four people.”

Gilbert, who works for the state department of education, said last week marked the first time she’d come back to work since the shootings. She said she is struggling with finding a way to return to her routine.

When asked if a trial would give her closure, she said, “No.” 

She then shook her head and asked, referring to Eaton’s plea, “Did I hear that right?” 

Outside, DeRaps declined to comment in detail, but provided a written statement that he insisted was speaking for himself and no one else. In it, he called Eaton “an evil, selfish coward.”  

“We can only hope that justice is served, and my heart goes out to all those affected by this needless tragedy,” he wrote. 

Sean Halsey, the father of Paige and Justin Halsey, said, “I think it’s a good first step. I’m glad that he’s not going to be release on bail or anything like that.”  

Halsey said his children are still recovering, but sounded a hopeful note.

“They’re amazed, all the doctors, with how well they’ve healed,” he said.

The charges stem from two separate incidents of violence on the morning of April 18. Eaton’s parents had been staying with the Egers at 1459 Augusta Road in Bowdoin. Eaton’s mother had picked him up from a Maine prison on April 14. He had been serving two years for a sentence revocation, and had a lengthy criminal history in Maine, Kansas and Florida. 

On April 18 at about 9 a.m., a relative of the Egers called police to report finding blood and more than one firearm scattered in the home, along with at least one dead body. Police found both Egers and Eaton’s parents dead on the property. 

Less than two hours later, at about 10:30 a.m., police received multiple calls about someone shooting at cars on Interstate 295 near Exit 15 in Yarmouth. According to a written indictment from Cumberland County, Eaton was arrested at the scene and the Halseys were taken to the hospital with gunshot wounds. All three survived. 

On Friday, Angie Kensell, of Chelsea, was in the audience. She knew the Egers and the DeRaps family, and happened to be in a car on Interstate 295 on April 18. 

“He came up on my right-hand side, and started peppering my car with bullets,” she said of Eaton. 

Kensell said she couldn’t see what kind of firearm Eaton had, but said she saw Eaton shoot at the Halseys’ car. 

“He kept right on going and shot the next car,” she said.

Kensell said she was surprised with Eaton’s plea.

“It was a little surreal hearing the ‘not guiltys,’ but we’ll get through it,” she said.

According to the indictment, Eaton was “intending to cause multiple deaths.” The incident led to local businesses just off the highway being closed and a private school to go on lockdown while armed police searched the area.

The motive for the killings, if known, has not been disclosed. A criminal affidavit described a note found at the scene referring to “someone being freed of pain and that the writer of the note wanted a new life.”

The note was not signed. 

Sean Murphy reported for Spectrum News. With reporting by the Associated Press.