WOBURN, Mass. (AP) — The lawyer for a Maine man charged with beating his mother, his grandparents and his grandparents' caretaker to death with a baseball bat in Massachusetts says he will likely pursue an insanity defense.

Orion Krause was held without bail at a mental health facility after pleading not guilty Wednesday in Middlesex Superior Court to four counts of murder. He has been ruled competent for trial.

His lawyer, Edward Wayland, said after the proceedings that "I think mental illness will be the explanation for this event."

Krause, of Rockport, Maine, and a 2017 graduate of Oberlin College in Ohio, is charged with killing the victims in his grandparents Groton, Massachusetts, home last September.

The victims have been identified as Elizabeth Krause, Frank Darby Lackey III, Elizabeth Lackey, and Bertha Mae Parker.