A man found floating on a raft in the ocean off the coast of Rhode Island in 2016 after his boat sank has been indicted on charges alleging he killed his mother at sea to inherit the family’s estate.

The eight-count indictment released Tuesday in federal court in Burlington also says Nathan Carman shot and killed his grandfather, John Chakalos, in 2013 as part of an effort to defraud insurance companies, but he was not charged with that killing.

Carman was found in an inflatable raft eight days after he went fishing with his mother, who was never found. Carman’s attorney did not return a call seeking comment.