BURLINGTON, Vt. (AP) — The man charged with killing his mother at sea during a 2016 fishing trip off the coast of New England in what prosecutors say was a scheme to inherit millions of dollars has died, federal authorities said Thursday.

Nathan Carman, 29, of Vernon, Vermont, was scheduled to face trial in October. He had pleaded not guilty last year to fraud and first-degree murder in the death of his mother, Linda Carman of Middletown, Connecticut.

The eight-count indictment also says Carman shot and killed his wealthy grandfather John Chakalos at his home in Windsor, Connecticut, in 2013 but does not charge him with murder in his death.

In September 2016, Carman arranged a fishing trip with his mother, during which prosecutors say he planned to kill her and report that his boat sank and his mother disappeared in the accident.

He was found floating in an inflatable raft eight days after leaving a Rhode Island marina with his mother, who was never found. Prosecutors allege he altered the boat to make it more likely to sink. Carman denied that allegation.

In 2019, a federal judge in Rhode Island had decided that Carman contributed to sinking the 31-foot fishing boat, ruling in favor of an insurance company that had refused to pay an $85,000 claim for the boat’s loss.