A civil trial that began on Tuesday will determine whether insurance companies must cover an $85,000 claim from a Vermont man for his boat, which sank nearly three years ago off the New England coast.
Insurers are refusing to pay the claim, saying Carman made suspicious alterations to the 31-foot vessel before leaving Rhode Island with his mother on a fishing trip in September 2016.
Carman was floating in a life raft when he was picked up eight days later by the crew of a passing freighter. Linda Carman was never found and is presumed dead.
Carman has denied doing anything intended to make the boat unseaworthy.
U.S. District Court Judge John McConnell, who is hearing the non-jury case in a Providence federal court, reiterated at the outset of the trial ground rules that limit testimony to questions surrounding the validity of the insurance claim, and not any of the other questions that have swirled around Nathan Carman in recent years.
Carman's aunts believe he deliberately caused the boat to sink, and claim he was also responsible for the 2013 shooting death of their father in Connecticut.
Nathan Carman has been named by police as a "person of interest" in the killing of John Chakalos, 87, a wealthy real estate developer.
In-depth news coverage of the Greater Boston Area.
Carman, who arrived at the court on Tuesday carrying a large container of documents, has not been charged with any crime and has denied involvement in his grandfather's death.
The first witness in the trial was Brian Woods, of Plymouth, Massachusetts, who sold the boat, named "Chicken Pox," to Carman for $48,000 in 2015.
"I was concerned about his lack of respect for the ocean," said Woods, who testified that Carmen came alone to pick up the vessel and was driving the boat at too high a speed when he left Plymouth.
Woods also testified that when he later went to Rhode Island to get his license plates back, the vessel was in disarray and that Carman had removed a compass and left it on the floor of the boat.
Carman's lawyer, David Anderson, said in his opening statement that Woods took advantage of Carman's lack of experience when he sold him the rebuilt vessel, the Hartford Courant reported .
"He couldn't sell the boat until Nathan Carman came along who had more money than experience and he saw an opportunity to take advantage of him," the lawyer said.
An attorney representing the insurance company said during opening statements that an expert on hypothermia would testify that it was unlikely Carman could have been drifting in a life raft for more than a week before he was rescued, and that an oceanographic expert would present a tidal analysis casting doubt on Carmen's claims about what happened the day he said the boat sank.