The deaths of Gene Hackman and his wife remain a mystery as authorities confirm there were “no significant findings” of carbon monoxide or gas leaks at their New Mexico home.

The New Mexico Gas Co. conducted an investigation after the Oscar-winning actor; his wife, Betsy Arakawa; and their dog were found dead last week.

Authorities found Hackman, 95, in a mudroom near the kitchen of his Santa Fe home, according to a search warrant. Arakawa, 65, was on the floor of a bathroom, and a German shepherd was discovered about 10 feet from her in a closet in the bathroom.

Two other dogs were found alive on the property.

On Tuesday, the Santa Fe County Sheriff’s Office released a brief update on the investigation, saying it had received the gas company’s findings.