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.

Actor Gene Hackman, his wife Betsy Arakawa, and their dog were found dead in their Santa Fe home, in a scene that one detective had deemed “suspicious enough in nature to require a thorough search and investigation.

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