The defense for a 23-year-old Rockport man accused of murder — in the September 2017 deaths of his mother, her parents, and their caretaker — formally entered an insanity plea Thursday.

Defense attorney Edward Wayland said Thursday, March 7, that he officially notified the commonwealth (prosecution) that he will be asserting a defense for Orion Krause based on lack of criminal responsibility due to mental disease or defect.

The case had been scheduled to go to trial beginning April 22 in Middlesex County Superior Court in Lowell, Mass. That will now be delayed.

The April 22 date will now be a status hearing to see where the prosecution is in its independent evaluation of Krause, the defense attorney said.

A spokeswoman for the Massachusetts Attorney General's Office said Thursday there is no estimate on when the evaluation will be complete. She said that because it is a pending case, the agency could not comment further.

Wayland said the commonwealth does its own evaluation, and if its expert disagrees with the defense, then there would be a trial.

Krause was indicted in March 2018 by a Middlesex County grand jury on four counts of first-degree murder. He pleaded not guilty at his arraignment in April 2018.

First-degree murder carries a mandatory sentence of life in prison.

Krause has been held in jail since his arrest Sept. 8, 2017, for the murder of his 60-year-old mother, Elizabeth "Buffy" Krause, of Rockport; her parents, Frank Darby Lackey III, 89, and Elizabeth Lackey, 85, both of Groton, Mass.; and the grandparents' caretaker, Bertha Mae Parker, 68, also of Groton.

According to police reports, Krause confessed to police that he had killed his family with a baseball bat and said he had "freed" them.

A judge ruled in October 2017 that Krause was competent to stand trial.

Documents filed in court after his arrest detailed that his mother had called police from her home in Rockport the night before the murders, concerned about whether he might harm himself.

She later told the dispatcher that her son was a "very mild soul," and that there were no drugs involved.

About 20 hours later, police were called to the Lackeys' home in Groton and found the bodies of the four victims.

An hour before their bodies were found, a professor with whom Orion Krause studied at Oberlin Conservatory in Oberlin, Ohio, phoned Rockport police to tell them that Krause had called to say he planned to kill his mother.

Oberlin College Prof. Jamey Haddad reported that Krause stated he had "done something bad," and had stolen some money and his mother’s car. Krause stated to Haddad twice during the conversation, "I think I have to kill my mom." The professor's wife had called police in Maine after trying to reach Orion Krause's mother.

Police said Orion Krause had called his mother and said he was in Boston and needed  a ride home. Police have not said what happened to the car he had been driving.

When his mother picked him up, she took him to her parents' home in Groton, located about 40 miles northwest of Boston.

Orion Krause stopped, naked, covered in mud, with some blood on him, at a home in his grandparents' neighborhood to tell the residents he had killed four people.

Krause repeated his statement to police that he had killed four people and identified who they were to police, according to the police report.

Orion Krause also told a nurse during a medical evaluation after his arrest that he used heroin, according to the police reports.

Krause was a 2013 graduate of Camden Hills Regional High School in Rockport and graduated in May 2017 from Oberlin, where he studied music.

Friends said that Krause was a kind, musically gifted person.

Rockport police had one contact with Krause about a year before the killings, but the details of that matter have not been released. Rockport/Camden Police Chief Randy Gagne said it was not a criminal matter.