VERNON, Vt. (CBS/AP) -- A day after a man who was lost at sea for a week returned home, search warrants from Connecticut and Rhode Island are raising concerns about his past.
Nathan Carman, 22, and his mother, Linda Carman, 54, went missing after leaving on a fishing trip September 18.
A week after the mother and son disappeared, the Coast Guard suspended their search for the pair--but Nathan was found alive in a life raft on Sunday, 100 miles south of Martha's Vineyard.
His mother remains missing and is presumed dead. The Coast Guard does not believe she could still be alive, so the search for her was terminated.
Now, authorities are trying to find out more about the boating mishap and whether or not Nathan had a role in the mysterious and ill-fated trip--and a warrant from 2014 shows that he was once a suspect in the still-unsolved murder of his wealthy grandfather.
Vermont Home Searched
Before Carman had even returned to land, South Kingstown, Rhode Island Police searched his Vernon, Vermont home Monday, seizing several items--and the warrant authorizing that search shows authorities are looking for evidence of reckless endangerment.
South Kingstown police did not immediately return calls seeking comment, but their search warrant indicates authorities think Carman was handling some repairs on the motor of his boat, the Chicken Pox, himself, and that the vessel might not have been seaworthy, which could support a reckless endangerment charge.
Carman grew up in Middletown, Connecticut, but bought the home in Vernon two years ago, where he returned Tuesday night.
Officers seized a modem, a Garman SIM card, and a letter written by Nathan from that home.
A police affidavit issued to obtain the search warrant also "indicates that Linda and Nathan had different intentions as to the final destination of the fishing trip."
Linda Carman, it states, thought they were going 20 miles off shore. Nathan, according to people he spoke with before he left, had other plans to take them roughly 100 miles out.
"I thought he said the canyons which are off Block Island," Mike Iozzi, who struck up a casual conversation with Nathan hours before he left the dock, told WBZ-TV. "I didn't see him with fishing poles. I didn't even see him with food."
Linda Carman had told her close friend that she and her son would take the boat out toward Block Island for an overnight fishing trip.
"I'm hoping for lots of answers," said Sharon Hartstein, a family friend. "I want to know if there's still hope for Linda, I want to know where they were, and what happened."
A police affidavit says surveillance video shows a mother and son arriving at a Rhode Island marina and preparing for their ill-fated fishing trip. Ram Point Marina in South Kingstown, Rhode Island, is refusing to release the video to news outlets.
A woman who works at the marina tells The Associated Press that Nathan Carman rented a slip there for the season. It was his first season there.
"A Primary Person Of Interest"
This isn't the first time Nathan Carman has faced scrutiny.
He was once considered by police to be a suspect in the unsolved murder of his wealthy grandfather--and during the investigation, one person at his apartment complex called him "a time bomb waiting to go off."
Linda Carman's father, 87-year-old John Chakalos, was killed three years ago in Windsor, Connecticut.
A source confirmed to WBZ-TV's sister station WFSB in Hartford that Nathan Carman was once "a primary person of interest" in that murder. Windsor police Capt. Thomas LePore said Wednesday that the case is still open and that Carman remains a "person of interest."
In the course of investigating the killing, authorities said in court papers that they found Carman's handwritten notes on making explosives, seized a shotgun and other weaponry from his Middletown, Connecticut, apartment, and learned from family members that he once held another child "hostage" with a knife.
They also said Carman had had several alarming episodes while he was a high school student in Connecticut. Those episodes were not explained.
According to court documents obtained by the Hartford Courant, Windsor police submitted an arrest warrant in July 2014 for Carman on a murder charge, but that warrant was returned unsigned with a request from the prosecutor for further information.
That warrant also named Carman as the last known person to see his grandfather alive on Dec. 20, 2013, because he had dinner with him at his home in Windsor. Chakalos was found dead the next morning. He had been shot three times.
The warrant notes that Nathan's story about where he was during the estimated time of his grandfather's murder was inconsistent. In addition, police found a gun and ammunition in his home, as well as a receipt for a gun matching the caliber of the murder weapon.
After Chakalos's murder, the warrant states, Nathan discarded his computer hard drive and GPS. He also refused a polygraph test.
He has Asperger's syndrome, a higher-functioning form of autism. Five years ago, he disappeared from his home, upset over the death of his horse, and was found days later in Virginia.
Sources told Windsor police he "was capable of violence when his coping mechanisms were challenged." Some of Carman's family members told police that, concerned for their safety, they had hired armed private security to protect them in their homes from Nathan.
Linda Carman's mother, Rita Chakalos, died of cancer just weeks before her father was killed. John and Rita Chakalos were philanthropists who split their time between Connecticut and Chesterfield, New Hampshire, where they had an estate known for its massive holiday lights display.
A will shows John Chakalos left an estate worth more than $42 million to his four adult daughters.
Nathan Carman told the Associated Press by phone Wednesday that he did not kill Chakalos--he says he was like a son to his grandfather.
In an interview Wednesday, Nathan's father, Clark Carman, also said Nathan had nothing to do with the murder.
"The past is the past, and what I want to say about that is, I wish the press would leave it alone, because he was not involved with his grandfather, with his mother," Clark Carman said Wednesday. "It was a pure accident, and he would never do anything like that."
"He's a good kid," Clark said. "He loved his grandfather. It's all being drudged up, and I really hate to see that, because there's no substance to it."
"Why didn't he see us? Why didn't we see him?"
Carman arrived in Boston Tuesday morning on the freighter that picked him up two days before, the Orient Lucky, and a Coast Guard boat took him from the freighter to a survivor debrief at the Coast Guard base in Boston.
After the debrief, Nathan left the Coast Guard base with his father, Clark, who flew in from his home in California.
He returned to his home in Vernon, Vermont Tuesday night, and spoke to WBZ-TV's Nicole Jacobs Wednesday morning.
"I just want to thank the public for their prayers and for their concern for both myself and my mother," he said.
But there are lingering questions about what happened at sea.
Coast Guard Petty Officer 3rd Class Nicole Groll wondered how their exhaustive search failed to locate Nathan.
"He said his boat sunk off Block Canyon, and we scoured 62,000 nautical miles of sea," she said. "He was found in the search area, his boat went down in the search area. Why didn't he see us? Why didn't we see him?"
Carman told Coast Guard officials that his boat began taking on water, and while he made it to the life raft, his mother did not.
There was no mayday call and no radio transmission of any kind from the fishing boat, according to the Coast Guard. On Tuesday, the Coast Guard released audio of their conversation with Nathan after he was rescued by the freighter.
"Mom and I, two people, myself and my mom were fishing on Block Canyon," Nathan said. "There was a funny noise in the engine compartment, I looked and saw a lot of water."
"I had my mom bring in the reel, I brought the safety stuff forward," Nathan said. "I was bringing one of the safety bags forward and the boat stopped out under my feet. When I saw the life raft, I did not see my Mom. Have you found her?"
Coast Guard Search and Rescue Controller Richard Arsenault responded, "No, we haven't been able to find her yet."
Nathan told Arsenault that after he got to the life raft, he began whistling and calling and did not see his mom.
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