Nathan Carman is set to be arraigned Wednesday on charges that he killed his mother on a 2016 fishing trip in an effort to claim an inheritance and an $85,000 insurance policy.

In September 2016, the US Coast Guard found Carman, then 22, drifting at sea off the coast of Rhode Island. He told investigators that he had been on a fishing trip with his mother Linda, who was nowhere to be found, when the boat sank.

“I didn’t know we were sinking,” Carman said in a 2016 interview with ABC News. “I knew we had a problem, but I didn’t know we were sinking until we sank.”

But on Tuesday, the 28-year-old Carman of Vernon, VT, was arrested on an eight-count indictment that charges him with murdering Linda Carman while on the 2016 fishing trip off the Rhode Island coast.

Federal agents execute a search warrant at Nathan Carman’s residence in Vernon, Vt., after he was arrested and charged with the murders of his grandfather and mother on Tuesday. (Kristopher Radder/The Brattleboro Reformer via AP)

Along with the charge of murder “on the high seas,” the indictment alleges Carman shot and killed his grandfather John Chakalos in 2013 as part of an effort to defraud insurance companies

In a statement, the executor of Chakalos’ estate said, “The Vermont United States Attorney appears to have completed an intensive and a thorough investigation of all of the facts surrounding the crimes. I hope today’s events help the family in their search for justice and closure.”

The indictment also alleges Carman tried to defraud the company that insured his fishing boat. The insurers claimed he made changes to the structure of the boat beforehand, causing it to sink. He filed a lawsuit against the insurance companies, but lost.

“I almost feel like I have a responsibility for my mom to make sure the truth comes out,” Carman said in a 2019 interview during closing arguments. “To have made claims against me that are so tremendous I don’t even feel like I can walk away from them.”

Carman could face mandatory life imprisonment if convicted for murder on the high seas and a potential penalty of up to 30 years of imprisonment for each fraud charge.