HARTFORD, Conn. (AP) — A Vermont man accused by relatives of killing his millionaire grandfather in Connecticut for inheritance money says in new court documents there is stronger evidence a woman he describes as his grandfather’s mistress was involved in the killing.

Nathan Carman’s lawyer filed the documents Monday in federal court in Providence, Rhode Island.

Carman’s grandfather, John Chakalos, was shot at his Windsor, Connecticut, home in 2013. Police have said Carman was a suspect, but never filed charges.

Carman alleges robbery could have been a motive for his grandfather’s mistress. The woman is not named in documents.

Relatives accuse Carman of killing his grandfather and possibly his mother, who disappeared during a 2016 fishing trip with her son and is presumed dead. Monday’s court filing came in a case over insurance money for Carman’s boat.

Dan Small, an attorney for the Chakalos family, released the following statement on their behalf Monday, in response to Carman’s claims:

“Nathan’s shameful attack on his Grandfather today shows there is no depth to which he will not sink to avoid producing his gun, which is the probable murder weapon.  Now he is trying to cast blame on his own Aunt, even though she willingly took and passed a police lie detector test, while Nathan refused, and she cooperated fully and honestly with the police, while Nathan lied repeatedly, including about this very gun.  Every day that passes in these legal proceedings shows even more clearly that Nathan’s behavior is calculated, evasive, and ultimately, guilty.”