'20/20' FEATURES INTERVIEW WITH MAN RESCUED AFTER WEEK LOST AT SEA DURING WHICH HIS MOTHER DIED

Hour Reports Latest Details and Previews Lawsuit Filed by Aunts

'20/20: Lost at Sea' Airs Friday, Aug. 24 (10:01 - 11:00 p.m. EDT), on ABC

A tragic accident or foul play? It was a story that made national headlines and "20/20" features an interview with Nathan Carman about his rescue from the ill-fated fishing trip that claimed his mother Linda's life. Nathan claims it was an accident that sunk his fishing boat, but authorities are still investigating the circumstances of Linda's disappearance. The hour explores the latest details and previews the lawsuit filed by Nathan's aunts, which claims that he did improper work on the boat which caused it to sink, leading to Linda's death. "20/20: Lost at Sea" airs Friday, Aug. 24 (10:01-11:00 p.m. EDT), on ABC. (Rebroadcast. ABC OAD: 2/3/17)

On Sept. 17, 2016, Nathan and Linda left a Rhode Island marina, sailing far out to sea to fish for tuna. When they did not return the Coast Guard sent out a search team. Seven days later a freighter rescued Nathan from a small life raft, but Linda was nowhere to be found. Nathan claims that after the boat made a "funny" noise, it began to take on water and started to sink. He was not able to find his mother and never saw her again. The report also includes interviews with Captain Zhao Hengdong, captain of the freighter that rescued Nathan; psychologist Dr. Rebecca Sachs; Captain Dave McCormick, who is familiar with the Rhode Island marina; Mike Iozzi, a regular visitor to the area and more.

Nathan told "20/20" that conditions were good the day they set out to sea, but McCormick, who says he was out on the same waters hours before, disagrees. This is not the first time Nathan was the last person to see a family member before their questionable death. Three years earlier, Nathan was the last person to see his grandfather John Chakalos before he was shot and killed. Authorities were suspicious of Nathan at the time, but no charges were ever filed. Nathan's aunts have also filed a lawsuit accusing him of killing his grandfather in an attempt to prevent Nathan from receiving money from his grandfather's estate. Nathan claims that he is innocent and that he was not responsible for the death of his mother or grandfather. He believes that because he has Asperger's syndrome, which is on the autism spectrum, he is being misunderstood and targeted.

"20/20" is anchored by David Muir and Amy Robach. David Sloan is senior executive producer.