DUXBURY, MASS. (WHDH) - A 22-year-old man was convicted Thursday on a charge of involuntary manslaughter nearly three years after prosecutors said he killed his father in Duxbury. 

Jack Callahan was found guilty following an eight-day trial. He is set to be sentenced on May 3, according to the Plymouth County District Attorney’s office.

The incident in question happened near 2 a.m. on June 28, 2021.

“Duxbury Police received a call to report that Jack Callahan, then 19, was acting erratically and that his father, Scott Callahan, 57, was missing in the area of Island Creek Pond at Crocker Park,” the DA’s office said.

Police responded to the scene on Sampson Street in town and found Jack Callahan “distraught and hyperventilating,” according to the DA’s office. Around the same time, officials said, emergency crews found Scott Callahan submerged in nearby Island Creek Pond at Crocker Park. 

“EMS performed life-saving measures and he was transported to Beth Israel Deaconess Hospital-Plymouth, where he was pronounced dead,” the DA’s office said.

The DA’s office said prosecutors presented evidence to jurors that Jack Callahan traveled to Boston to meet up with his father, retrieve him and return to Duxbury. 

“The two took a ride-share vehicle home from Boston, and after midnight on June 28, the ride-share dropped the two men off in the vicinity of Island Creek Pond,” the DA’s office said. “There a physical altercation took place between the pair.”

Among allegations, investigators said Jack Callahan believed his father was possessed by a demon. Prosecutors said Jack told police he held his father underwater in an attempt to baptize him.

Scott Callahan’s cause of death was ruled to be drowning, according to the DA’s office.

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