A man found floating on a raft off the coast of New England in 2016 after his boat sank was charged Tuesday with killing his mother at sea to inherit the family’s estate. The eight-count indictment released in federal court in Burlington, also says Nathan Carman shot and killed his grandfather, John Chakalos, at his home in Windsor, Connecticut, 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 leaving a Rhode Island marina to go fishing with his mother, Linda Carman, who was never found. Carman, 28, of Vernon, Vermont, was arrested Tuesday. He’s due in federal court Wednesday in Rutland.