Santa Fe County Sheriff Aden Mendoza has broken the leading theory behind the couple’s mysterious deaths

Gene Hackman and his wife Betsy Arakawa have tested negative for carbon monoxide poisoning, it has been revealed.

Santa Fe County Sheriff Aden Mendoza confirmed the tests in a press conference on Friday.

He said he had spoken with the pathologist from the New Mexico office of the medical investigator, who said that both Hackman and Arakawa tested negative for carbon monoxide.

It comes after the Oscar-winning actor’s daughter Elizabeth said his family believed that carbon monoxide poisioning was behind the couple’s deaths.

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She told TMZ that while the exact cause remains unclear, they believe toxic fumes could have been a factor.

Elizabeth also told TMZ police did not find any signs of foul play at the actor’s home.

The couple’s bodies were discovered in different rooms of their Sante Fe homes earlier this week.

It is believed they could have been dead for some time as reports suggest the bodies had ‘signs of mummification’.

Sheriff Mendoza said: “An initial interrogation was conducted of Mr Hackman’s pacemaker.

“This revealed that his last event was recorded on February 17, 2025, I was advised that a more thorough investigation will be completed.”

He also said it could take months to uncover the actual cause of death.

A crucial toxicology report could take months to be released.

Investigators are trying to figure out the last time anyone saw or spoke to them, Mendoza told NBC’s Today show on Friday.

The chilling 911 call reporting the deaths has since been released.

A panicked male voice is heard on the call, telling the dispatcher that he has found two motionless bodies.

They urgently request help at the Santa Fe, New Mexico residence.

TMZ reported that the caller, whose identity was withheld, was audibly upset, repeatedly exclaiming ‘Damn’ and sniffling.