Gene Hackman's dog, Zinna, likely died of dehydration and starvation.
The female Kelpie cross was found dead alongside its owners, Gene Hackman and his wife Betsy Arakawa on 26 February.
Now Santa Fe County animal control has revealed that dehydration and starvation probably led to its death. However, the dog's body had already shown signs of partial mummification, making it hard to know exactly what happened.
Santa Fe County animal control also noted that there was no evidence of infectious disease, trauma or poisoning, and Zinna's stomach was empty apart from small amounts of hair and bile.
There were two other dogs, Bear and Nikita, on the property when Zinna, Hackman and Arakawa were found.
Bear and Nikita helped first responders find the bodies of their owners, according to Santa Fe Fire Department Chief Brian Moya, who revealed that the dogs had kept running up to them and barking, then running in a different direction.
"They realised (the dog) was trying to say, 'Hey, come over here! Come over here!'" he said.
Joey Padilla owns a dog shelter that has been caring for Bear and Nikita since they were found.
"(Zinna) was always attached to Betsy at the hip and it was a beautiful relationship," he told Associated Press. "Zinna went from being a returned shelter dog to this incredible companion under Betsy's hand."
It was revealed last week that Arakawa had died from hantavirus, a flu-like virus linked to rodent droppings. Hackman died around a week later, from heart disease, high blood pressure and advanced Alzheimer's disease.
