Gene Hackman and his wife, Betsy Arakawa, tested negative for carbon monoxide poisoning, the Santa Fe Sheriffs Department in New Mexico said Friday, one day after they were found dead with their dog.

Santa Fe County Sheriff Adan Mendoza told NBC's “Today” show that investigators were trying to sort out conflicting stories about the doors. He said several doors were unlocked and a rear door was open, which allowed two dogs that survived to go in and out. He also said he thinks the front door was closed but unlocked.

Oscar-winning actor Gene Hackman, 95, and his wife, classical pianist Betsy Arakawa, 63, were found dead Wednesday in their Santa Fe, New Mexico, home, authorities confirmed to HuffPost. One of the couple’s dogs also died.