A Sagadahoc County Grand Jury on Friday indicted a man accused of shooting his parents and two family friends in the town of Bowdoin in April.

The Maine Attorney General’s office confirmed Friday afternoon that Joseph Eaton, 34, had been indicted on 16 charges, including possession of a firearm by a felon, nine counts of theft of a firearm and four counts of murder.

A Cumberland County Grand Jury also indicted Eaton on June 9 on 11 charges, including three counts of attempted murder with the use of a firearm.

Eaton was arrested days after his release from prison on April 18, a morning marked by violence. First, police said, there was a shooting at a home at at 1459 Augusta Road in Bowdoin. Robert Eger, 72, and Patricia Eger and their friends David Eaton, 66, and Cynthia Eaton, 63, were found dead at the home just after 9 a.m.

The indictment released Friday includes 16 charges in total, including nine counts of theft of a firearm and a count of possession of a firearm by a prohibited person. It states that he stole nine firearms from the Egers.

The indictment also charges Eaton with aggravated cruelty to animals and states that he killed Max, the Egers' goldendoodle, “in a manner manifesting a depraved indifference to animal life or suffering.”

The Cumberland County indictments relate to accusations that Eaton went on a shooting spree, also on April 18 at around 10:30 a.m., on Interstate 295 near Exit 15 in Yarmouth. Three people — Justin Halsey, 29, Paige Halsey, 25, and Sean Halsey, 41 — were shot before Eaton was arrested. The three victims survived.

Eaton was “intending to cause multiple deaths” when he fired the shots from the highway, the indictment stated.

Eaton is due in court in Bath on June 28 for a dispositional conference. He has been represented in the case by attorney Andrew Wright of Brunswick. Wright did not return a call seeking comment on Friday.

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. He first appeared in court later that week, though he has not yet entered a plea.

Eaton’s parents were staying with their longtime friends after his mother picked him up from a Maine prison on April 14, where he served about two years for a sentence revocation after completing a sentence in Florida for aggravated assault, part of a long criminal history in Maine, Kansas and Florida.

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.”

With reporting by the Associated Press.