Updated

SANTA FE, N.M. — Gene Hackman died due to hypertensive atherosclerosis cardiovascular disease, with Alzheimer's disease as a significant contributing factor, New Mexico officials confirmed Friday. He was likely alone in the home for about a week, until he died around Feb. 18, which was the last time activity was recorded on his pacemaker.

His wife, Betsy (Arakawa) Hackman, died due to Hantavirus Pulmonary Syndrome, which is transmitted from animals to humans and is commonly found in rodents, the New Mexico Department of Health confirmed. Her autopsy determined the manner of death as natural. Authorities believe she died on or about Feb. 11. 

Chief Medical Investigator Dr. Heather Jarrell performed a full autopsy on Hackman the day after his body was discovered, which showed "severe heart disease, including multiple surgical procedures involving the heart, evidence of prior heart attacks, and severe changes of the kidneys due to chronic high blood pressure."

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Gene Hackman and wife Betsy in 1994

Gene Hackman and Betsy Arakawa were both found dead in their Santa Fe, New Mexico, home on Feb. 26. (Ron Galella/Ron Galella Collection via Getty Images)

She added, "Examination of the brain showed advanced Alzheimer's disease as well as blood vessel changes in the brain secondary to chronic high blood pressure."

Jarrell noted that Hackman's pacemaker data indicated "abnormal rhythm of atrial fibrillation" on Feb. 18. She said it was "reasonable to conclude" Arakawa died the week before Hackman, with the actor’s death likely on Feb. 18.

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"Based on the circumstances, it is reasonable to conclude that [Arakawa] passed away first, with February 11th being the last time that she was known to be alive," Jarrell said. 

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Investigators determined that Arakawa's last known activities within the community included a veterinary visit on Feb. 9. Two days later, she was seen at a local grocery store, a pharmacy and a pet store before she returned home to their gated community at around 5:15 p.m. on Feb. 11, Sheriff Adan Mendoza said during the news conference. 

When asked if authorities believed Hackman was able to live on his own and survive after his wife died, Jarrell noted that the Oscar-winning actor was in "a very poor state of health."

"Based on the circumstances, it is reasonable to conclude that Miss Hackman passed away first, with February 11th being the last time that she was known to be alive."

— Dr. Heather Jarrell

"Mr. Hackman showed evidence of advanced Alzheimer's disease," Jarrell said. "I'm not aware of what his normal daily functioning capability was. He was in a very poor state of health, and he had significant heart disease. And I think ultimately that is what resulted in his, in his death."

Gene Hackman's home is seen surrounded by police after his death

The entrance to the gated community where actor Gene Hackman, his wife Betsy Arakawa and their dog were found dead in their home in Santa Fe, New Mexico, is shown on Feb. 27. (AP Photo/Roberto Rosales)

Jarrell was unable to detect evidence of dehydration, and did find "poor kidney function" during the autopsy, but there was "no food in his stomach, which means he had not eaten recently."

"He was in an advanced state of Alzheimer's, and it's quite possible that he was not aware that she was deceased," the medical examiner said.

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"He was in an advanced state of Alzheimer's, and it's quite possible that he was not aware that she was deceased."

— Dr. Heather Jarrell

Jarrell explained that hantavirus is characterized by "flu-like symptoms consisting of fever, muscle aches, cough, sometimes vomiting and diarrhea that can progress to shortness of breath and cardiac or heart failure and lung failure."

"This occurs after a one- to eight-week exposure to excrement from a, primarily, particular mouse species, that carries hantavirus," she said. Hantavirus strains in the U.S. are not transmissible from person to person, but rather from animals to humans.

WATCH: BETSY ARAKAWA VISITED SANTA FE SPROUTS LOCATION BEFORE HER DEATH

Dr. Erin Phipps, New Mexico State Veterinarian with the New Mexico Department of Health, explained that the state has confirmed between one and seven cases of the rare infection in humans each year, ending in 2024.

"We have identified 136 infections over the past 50 years in New Mexico residents, five of these in Santa Fe County," Phipps said. "This is a serious disease. Forty-two percent of these infections here in New Mexico were fatal."

Hackman and Arakawa, who were married for more than 30 years, and one of their dogs were found dead in their Santa Fe home on Feb. 26 by maintenance workers.

Actor Gene Hackman and his wife.

Gene Hackman and his wife, Betsy Arakawa Hackman, were married for 30 years. (Getty Images)

Mendoza indicated during the news conference that Zinna, the dog that had died, may have recently undergone a procedure which could "explain why the dog was in a crate" when she died.

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Detectives initially described the couple's deaths as "suspicious enough in nature to require a thorough search and investigation," according to a search warrant affidavit obtained by Fox News Digital. 

Officials confirmed that no external trauma was seen on either Hackman or Arakawa, and New Mexico authorities promptly launched a criminal investigation into their deaths. 

Gene Hackman's home is seen surrounded by police after his death

Law enforcement officials talk outside the home of actor Gene Hackman on Feb. 27 in Santa Fe, New Mexico. Hackman, his wife Betsy Arakawa and one of their dogs were found dead in the home a day earlier. (AP Photo/Roberto Rosales)

Hackman and Arakawa previously tested negative for carbon monoxide, Mendoza confirmed last week. Their residence was tested for the colorless, odorless gas and was cleared by the Santa Fe City Fire Department after authorities were unable to find evidence of a carbon monoxide leak or poisoning.

Additionally, the New Mexico Gas Company confirmed on Tuesday "no significant findings" after conducting an extensive investigation for gas leaks and carbon monoxide at the couple's secluded home.

A "minuscule leak (0.33% gas in air – not a lethal amount) at one of the stove burners" was discovered, according to a release obtained by Fox News Digital. Four code enforcement violations were also noted involving "a water heater and gas log lighters installed in three fireplaces." 

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Mendoza previously said last week that the last recorded activity on Hackman's pacemaker occurred on Feb. 17. Authorities assumed this was his last day alive, as the Oscar winner's body was not discovered for nine more days.

"According to the pathologist, I think that is a very good assumption that that was his last day of life," Mendoza said. 

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