The Duxbury, Massachusetts, man accused of killing his father in June is due back in court Thursday.
Jack Callahan, 19, allegedly dunked the head of his 57-year-old father, Scott Callahan, in a pond in a bid to baptize and rid him of demons on June 28 at Island Creek Pond in Duxbury.
Jack Callahan pleaded not guilty to murder charges in Plymouth District Court in June.
Duxbury police received a call just after 2 a.m. on June 28 from a woman, Jack's mother and Scott's former husband, who said her 19-year-old son had come home saying his father was missing, prosecutors said.
Investigators learned that the father and son had been dropped off at Crocker Park by an Uber driver.
Jack Callahan allegedly said he and his father were heading to Duxbury, but his mother would not allow the older man in the house. Instead, the two went to the pond.