(Boston) — A 22-year-old man rescued from a life raft after a fishing trip that left his mother missing and presumed dead had been a suspect in the still-unsolved 2013 slaying of his rich grandfather, adding to the multitude of questions swirling around him and what happened at sea. Nathan Carman was picked up by a freighter Sunday 100 miles off the Massachusetts coast after what he said was a week adrift that began when his 31-foot aluminum fishing boat inexplicably sank during a mother-and-son outing. Coast Guard officials interviewed Carman, and police searched his home in Vermont as part of an investigation into the ill-fated trip.