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.

Authorities in New Mexico continue to investigate the cause of death of actor Gene Hackman and his wife​ Betsy Arakawa, but they say it does not appear to be carbon monoxide poisoning.

Gene Hackman and his wife Betsy Arakawa both tested negative for carbon monoxide after their deaths, Adan Mendoza, the sheriff of Santa Fe County in New Mexico, said at a press conference on Friday, Feb. 28.