Initial autopsy results after the mysterious and “suspicious” deaths of Hollywood actor Gene Hackman and his wife have been released.

The Oscar-winner, Betsy Arakawa and one of their dogs were discovered by a maintenance worker at their home in Santa Fe, New Mexico.

Hackman, 95, was dead in an entryway, and classical pianist Arakawa, 65, was found in a bathroom next to a space heater.

Santa Fe County Sheriff Adam Mendoza on Saturday (AEDT) said initial autopsy results revealed there was “no external trauma to either”.

“There were no apparent signs of foul play. The manner and cause of death has not been determined,” said Mendoza.

“The official results of the autopsy and toxicology reports are pending. This remains an open investigation.”

Deepening the mystery, Mendoza told NBC’s Today Show that the couple could have been dead for “several days, possibly even up to a couple of weeks”.

A search warrant stated that Arakawa’s body showed signs of “mummification” of the hands and feet — a process which takes time.

Her body had undergone decomposition and her face was bloated, said an officer’s affidavit on the search warrant.

Natural mummification is a “rare phenomenon” that needs several weeks or months to occur, according to a 2023 scientific research paper.

“Many factors could affect the mummification process, but the most important ones are dry air, good ventilation, solar radiation, and high temperature,” said the paper published in Cureus.

Meanwhile, TMZ said it had obtained the full list of items that police seized from the house during a search.

They included thyroid medication, Tylenol and Diltiazem — a calcium-blocker used to treat high blood pressure and other heart-related issues, reports TMZ.

Police took records from MyQuest — a healthcare website used to check test results, schedule appointments and keep track of one’s health history.

They also took a 2025 calendar and two cell phones.

Open prescription bottle and pills had been found scattered on a countertop near Arakawa.

Actor Gene Hackman and classical pianist wife Betsy Arakawa in 1993. Photo: AAP

Denise Avila, a sheriff’s office spokesperson, said there was no indication they had been shot or had any wounds.

The New Mexico Gas Co tested the gas lines in and around the home after the bodies were discovered, according to the warrant.

At the time, it didn’t find any signs of problems and the Fire Department found no signs of a carbon monoxide leak or poisoning.

According to the search warrant affidavit, a maintenance worker reported that the home’s front door was open when he arrived to do routine work Wednesday (local time), and he called police after finding the bodies.

But in an emergency call, the maintenance worker said he was unable to get inside when the operator asked whether the people in the house were breathing.

“I have no idea,” the subdivision’s caretaker said. “I am not inside the house. It’s closed. It’s locked. I can’t go in. But I can see she’s laying down on the floor from the window.”

He and another worker later told authorities that they rarely saw the homeowners and their last contact with them had been about two weeks ago.

Hackman appeared to have fallen, a deputy observed. A cane was nearby.

A dead German shepherd was found in a bathroom closet near Arakawa, police said.

Santa Fe County Sheriff Adan Mendoza said during a press conference on Thursday that the dog was found in a kennel. Two healthy dogs were found on the property — one inside and one outside.

“There was no indication of a struggle,” Mendoza said.

“There was no indication of anything that was missing from the home or disturbed, you know, that would be indication that there was a crime that had occurred.”

The couple’s house in Santa Fe, New Mexico. Photo: AAP

Hackman routinely showed up on Hollywood lists of greatest American actors of the 20th century.

He could play virtually any kind of role, from comic book villain Lex Luthor in Superman to a coach finding redemption in the sentimental favourite Hoosiers.

Hackman was a five-time Oscar nominee who won best actor in a leading role for The French Connection in 1972 and best actor in a supporting role for Unforgiven two decades later.

His death comes just four days before this year’s ceremony.

Tributes quickly poured in from Hollywood.

“There was no finer actor than Gene,” actor-director Clint Eastwood, Hackman’s “Unforgiven” co-star, said in a statement. “Intense and instinctive. Never a false note. He was also a dear friend whom I will miss very much.”

Hackman met Arakawa, a classically trained pianist who grew up in Hawaii, when she was working part-time at a California gym in the mid-1980s. They soon moved in together and relocated to Santa Fe by the end of the decade.

Their Southwestern-style ranch on Old Sunset Trail sits on a hill in a gated community with views of the Rocky Mountains. The sprawling four-bedroom home on 2.4 hectares was built in 1997.

Hackman also co-wrote three novels, starting with the swashbuckler, Wake of the Perdido Star, with Daniel Lenihan in 1999, according to publisher Simon & Schuster. He then penned two by himself, concluding with Pursuit in 2013, about a female police officer on the tail of a predator.

In his first couple of decades in New Mexico, Hackman was often seen around the historic state capital, known as an artist enclave, tourism destination and retreat for celebrities.

In recent years, he was far less visible, though even the most mundane outings caught the attention of the press.

Aside from appearances at awards shows, he was rarely seen in the Hollywood social circuit and retired from acting about 20 years ago. His was the rare Hollywood retirement that actually lasted.

Hackman had three children from a previous marriage. He and Arakawa had no children together but were known for having German shepherds.

-with AAP