Gene Hackman and his wife Betsy were found dead in their Santa Fe, N.M., home on Feb. 26

When authorities went inside the two-story Santa Fe, N.M., home of Gene Hackman and his wife Betsy around 2 p.m. on Wed. Feb. 26, they spotted Betsy first.

Betsy, 65, was lying on her side on the floor of the bathroom near a countertop. She was dressed in dark gray sweatpants and a light color sweatshirt. An officer noticed a space heater near her head, suspecting that Betsy may have knocked over the heater when she fell.

Pills were scattered on the countertop.

The Santa Fe County Sheriff’s officer noted in a search warrant affidavit obtained by PEOPLE that Betsy showed signs of body decomposition, bloating in her face and mummification in both hands and feet.

The couple’s dog was found dead about 10 to 15 feet from Betsy in a closet in the bathroom.

Officers soon found Hackman, who was dressed in gray sweatpants and a blue long-sleeved T-shirt, lying in the home’s mudroom. A pair of sunglasses was found to the left of Hackman’s body. A walking cane was also found nearby. One of the officers suspected that Hackman had “suddenly fallen.”

Law enforcement officials talk outside the home of actor Gene Hackman on Thursday, Feb. 27, 2025 in Santa Fe, New Mexico. Roberto Rosales/AP

“(The officer) advised the male decedent also showed obvious signs of death, similar and consistent with the female decedent,” states the affidavit, which was obtained by PEOPLE.

After searching the home for signs of a break-in or forced entry, the officers determined “nothing appeared to be ‘out of place,’” according to the affidavit.

More than 10 days later, the cause of the couple’s deaths remains a mystery to the public.

“When you have bodies that are decomposed or haven’t been seen, and especially with people who haven’t been seen for a while, the first question in terms of trying to figure out what happened is figuring out the time of death,” forensic pathologist Judy Melinek tells PEOPLE. “And one way of figuring out the time of death is to look at markers at the scene, indicators of when was the last time, they were alive. And those tend to be more reliable than the anatomic markers once the body is badly decomposed.”

“In the early phases after death, we can rely on things like rigor mortis — the stiffening of the body — or algor mortis, which is the body temperature,” she says. “And we can use those to try to narrow down the postmortem interval, but once the body’s decomposed, it’s a lot harder to do.”

Melinek says investigators try to narrow down the timeline “by things like scene findings and circumstantial evidence.”

Gene Hackman and wife Betsy. Ron Galella/Ron Galella Collection via Getty

“When was the last time they were seen alive? When were they found dead? When did the mail start piling up? That indicates that nobody was going to the mailbox to pick it up. So, you can tell from the date stamp on the mail, when was the last time they logged into their computer or opened their phone or called anybody.”

Melinek also says that with bodies that have decomposed for 10 days or more, they “start to fall apart and there’s going to be certain organs that disintegrate and are no longer showing the anatomic markers that could help us figure out whether they were working or functioning properly.”

Mummification also complicates determining who died first.

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“You’re not going to be able to tell from the postmortem changes, because once you get to mummification then all bets are off,” James Gill, Chief Medical Examiner, with the Connecticut Office of the Chief Medical Examiner tells PEOPLE. “It depends where in the house they were, what were they wearing, all sorts of things can affect the postmortem changes. Once you get to that mummification stage there’s nothing to … be able to distinguish the two deaths timewise.”

“Generally dry environments, a person will mummify more quickly than in a non-dry environment,” he says. “Was that bathroom drier? What if the heater was on? That certainly could explain some advanced mummification. Heat generally accelerates decomposition. What kind of clothing are they wearing? Is he in front of a window with the sun coming in? Or is she in a closed room with no windows? All those factors can play a role in how quickly someone decomposes.”

Authorities previously announced that carbon monoxide poisoning had been ruled out as a cause of the deaths.