Five weeks before his wealthy grandfather was killed in 2013, Nathan Carman bought a rifle that was the same caliber as the murder weapon and rebuffed a gun dealer who suggested a “more economical brand” for his stated purpose of target shooting, court records show.

The details of the purchase by Carman, 24, were made public in documents filed Friday in US District Court in Rhode Island, where the insurer of Carman’s sunken boat is suing to block him from collecting a payout on the vessel.

Carman and his mother, Linda Carman, set sail in September 2016 from Point Judith, R.I., for a fishing trip on the boat, which sank more than 100 miles offshore. Nathan was rescued a week later, but his mother hasn’t been found.


The insurer alleges that Nathan Carman made suspicious alterations to the boat before the trip with the intention of sinking the vessel. He has denied intentionally harming his mother.

But with her presumed death, her share of her father John Chakalos’s $44 million estate would eventually go to Nathan, her only child.

Carman was the last person to see Chakalos alive before his death in December 2013, and police officials have asserted previously that Carman bought a Sig Sauer rifle identical in caliber to the one that killed his grandfather.

Police have labeled Carman a person of interest in Chakalos’s death, but he hasn’t been charged and has repeatedly denied killing his grandfather. The murder weapon hasn’t been located. Chakalos was found shot to death inside his Windsor, Conn., home on Dec. 20, 2013.

Friday’s filings in Rhode Island shed new light on the Sig Sauer that Carman purchased at Shooters Outpost in Hooksett, N.H. on Nov. 11, 2013.

In a written declaration, Jed Warner, a former sales associate at the store, said Carman came in that day and informed him that he wanted to buy a Sig Sauer.


“I asked him his intended use for the rifle and he replied, ‘target shooting,’ ” Warner said in the filing. “I told him if he was interested I could recommend a more economical brand but he replied, ‘No, I have done my research and this is what I want,’ referring to a Sig Sauer 716 Patrol Rifle. It was clear to me from our conversation that he had completely researched that particular model and he was very well-versed and familiar with it.”

Warner and Carman also talked about ammunition.

“We discussed that it [the Sig Sauer] was capable of firing both 7.62 NATO military caliber and more economical .308 commercial grade caliber ammunition interchangeably without any modification since those two rounds’ shells are virtually identical and can be loaded interchangeably in and fired from that model.”

Carman purchased the rifle for $2,099.99, according to court records. His lawyers didn’t immediately respond to a request for comment Friday.

The boat insurer is asking a Rhode Island judge to compel Carman to answer questions about his firearm purchase.

“Nathan Carman’s substantive deposition testimony should be ordered resumed on the topic of his purchase of that rifle and its whereabouts, including what he did with that rifle after purchasing it, did it kill his grandfather, why was it not found by search warrant, what has happened to it, how long did Nathan Carman possess it, and where is it now?” the insurer’s attorneys wrote. “If he still has possession, custody, or control of the rifle, he must bring it to the deposition (without ammunition).”


Carman also faces a separate lawsuit in New Hampshire, where his aunts are seeking to bar him from collecting funds from Chakalos’s estate.

Travis Andersen can be reached at travis.andersen@globe.com. Follow him on Twitter @TAGlobe.