Gene Hackman and his wife Betsy Arakawa tested negative for carbon monoxide in the initial results of the toxicology report, leading officials to rule out carbon monoxide as a cause of Hackman and Arakawa’s death, Sheriff Adan Mendoza said in a press conference on Friday.

Gene Hackman, his wife Betsy Arakawa and their dog were found dead in their home on Feb. 26, the Santa Fe County Sheriff’s office tells PEOPLE

Mr. Hackman, who was found dead with his wife and one of their dogs, had written novels and painted since leaving Hollywood behind for retirement in New Mexico.