Nathan Carman, the Vermont man at the center of separate probes into the murder of his wealthy grandfather and disappearance of his mother, wants to tap a trust controlled by his aunt to hire a lawyer to defend against a lawsuit brought by the aunt and her siblings, records show.

Details of the latest dispute between Carman and his aunt, Valerie Santilli, were contained in legal filings submitted earlier this month in a New Hampshire probate court, where Santilli and her sisters are suing Carman in an effort to block him from collecting millions from his grandfather’s estate.

Carman’s grandfather, the developer John Chakalos, was found shot to death in his Connecticut home in 2013. Carman, 24, was the last person to see Chakalos alive and had bought a gun that was the same caliber as the weapon used in the slaying, according to court records.

The murder weapon hasn’t been found. Police have labeled Carman a person of interest in the slaying, but he hasn’t been charged and adamantly denies killing his grandfather.

In a status report filed July 16 in the New Hampshire suit, Carman wrote that he’s asking a judge in Connecticut to remove Santilli as trustee of the Nathan Carman Family Trust and to order her to “make distributions from the trust’’ to him so he can retain a lawyer to defend against her civil action. A hearing on his request is scheduled for Aug. 7 in West Hartford, Conn.

Chakalos had set up the trust for Carman before he died.

Nathan Carman has faced additional scrutiny for his mother’s disappearance.

In September 2016, Carman and his mother set sail from Point Judith, R.I., for a fishing trip on his 31-foot aluminum boat, which sank during the trip. He was rescued a week later, but his mother hasn’t been found. In a separate lawsuit pending in Rhode Island, the boat’s insurer alleges that Carman made suspicious alterations to his boat before he set out with his mother, with the intention of sinking the vessel. He’s denied intentionally harming his mother.

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