Orion Krause, the 22-year-old Rockport man accused of killing four people in Massachusetts with a baseball bat, has been found competent to stand trial, his attorney said Friday.

Krause was ordered to be held at Bridgewater State Hospital to continue treatment, his attorney, Edward Wayland, said in an email.

The competency report has been impounded from public view, according to the clerk’s office at Ayer District Court, where Krause made his preliminary appearance.

Krause is expected to be indicted by the Middlesex District Attorney’s office. His next court date is Dec. 15 in Ayer, but if a grand jury indicts him before then, the case will be transferred to superior court, said Wendy A. Wilton, clerk-magistrate for Ayer District Court.

Krause is charged with killing his mother, Elizabeth Lackey Krause, 60; his grandparents, Frank Darby Lackey III, 89, and Elizabeth Lackey, 85; and their home health care worker, Bertha Mae Parker, 68, with a baseball bat at his grandparents’ home on Common Avenue in Groton Sept. 8.

Krause grew up on Monhegan Island and then Rockport, an affluent midcoast community. He was a talented jazz drummer and graduated from the Oberlin Conservatory of Music in Ohio last spring.

Friends and others who knew him and his family said the killings were entirely out of character.

Krause’s father, Alexander “Lexi” Krause, who spoke briefly to a reporter this month, said the tragedy highlights the need “to pay more attention to mental health,” but he didn’t address whether his son suffered from any mental illness.

Following the killings, Krause allegedly walked through a wooded area between his grandparents home and a neighboring house and removed his clothing. He appeared at the neighbor’s home muddied and smeared with blood.

The neighbor called police, who soon found a grisly scene inside the house.

Court documents unsealed in September included probable cause for Krause’s arrest and include written statements from four police officers who were at the crime scene or spoke with Krause.

Although detailed, the documents do not include any clear motive Krause may have had, other than a cryptic assessment that he “freed” the victims. They do, however, include an admission from Krause that he was a heroin user – a detail that had not previously been disclosed – although nothing in the documents indicates he used heroin immediately before the killings.

The documents detail how the neighbor, Wagner Alcocer, called 911 to report that a man, later identified as Krause, had shown up at his house.

Groton Police Officer Gordon Candow was one of the first to arrive.

“I walked up the step to the back patio and I could see a white male in his early twenties sitting in a patio chair,” he wrote. “The male was naked and it appeared he had rubbed mud all over his body. The male was also covered in thin cuts. When I approached him I asked, ‘Are you okay?’ and ‘What’s going on?’ The male stated, ‘I murdered four people.’ ”

Krause then told the officer who he had killed. When asked where it happened, he pointed toward the woods near Alcocer’s house and said, “somewhere over there.”

During questioning, Krause began singing and said, “I freed them,” according to police reports.

Police found the grandparents and Krause’s mother dead in the Lackeys’ house. The caregiver, Parker, was found outside, face down in a flowerbed. The documents do not indicate whether Parker was killed outside or whether she may have tried to flee.

Police gathered evidence from the scene, including a wooden baseball bat covered in blood.