A Vermont man pleaded not guilty to charges that he killed his mother at sea in an effort to inherit his family’s estate. Nathan Carman shouted “not guilty” to members of the media as he was led into court in Rutland, where cameras are not allowed. Six years ago, the Vernon man was rescued in a life raft off the coast of Martha’s Vineyard after a week stranded at sea. His mother, Linda Carman, was never found. Federal prosecutors say Carman killed his mother and altered the boat, causing it to sink. It is still not clear how she was killed. Her body was never found. Carman is also accused of murdering his grandfather, John Chakalos at his home in Windsor, Connecticut back in 2013, though he has not been charged for that murder. Authorities say both killings were part of a scheme to obtain money and property from the family trust. Carman faces a total of eight charges. If convicted for murder on the high seas, he faces a mandatory life sentence.