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.

Actor Gene Hackman, 95, and his wife, Betsy Arakawa, 65, both tested negative for carbon monoxide, authorities revealed Friday, amid an investigation after they were mysteriously found dead alongside one of their dogs at their home in Santa Fe,

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.