Before Gene Hackman faded from public view in his adopted hometown of Santa Fe, N.M., the locals would see the aging movie star on the golf course or in his truck or walking his beloved dogs in the enchanted western city, amid the mesquite, juniper and pinyon pine.

His wife, Betsy Arakawa, was often alongside him. There was much about his life that she managed. She set up the golf games with his friends. She policed his diet, given the heart trouble that had dogged him for decades. She diluted his wine with soda water. She typed and edited the novels he wrote by hand.

She also apparently took on the role of sole caregiver as he endured the devastating effects of Alzheimer’s. Thirty years his junior, she must have planned to see him to his end, in their home.

And so it was all the more jarring on Friday when authorities in New Mexico revealed more dark turns in the mystery of how the couple died last month in their four-bedroom house, hidden by trees at the end of a luxurious cul-de-sac east of the city.

Officials said the couple died of natural causes, he of heart disease and she of a rare viral infection. But it was Ms. Arakawa — the caregiver, lover, protector — who died first, perhaps on Feb. 11, leaving Mr. Hackman, 95 years old with advanced Alzheimer’s, alone in the house for days. He is believed to have died a week later, on Feb. 18.