The mystery regarding the cause of death for Academy Award-winning actor Gene Hackman and his wife Betsy Arakawa deepened with the release of new details.

Santa Fe, New Mexico, law enforcement officials found the couple, along with their dog, dead in their home during a wellness check on Wednesday afternoon.

Santa Fe County Sheriff Adan Mendoza confirmed the deaths, but he did not release a cause of death, other than to say no foul play was immediately suspected, nor a timeline for when the couple died, according to the Santa Fe New Mexican.

Some potential causes of death, given those facts, would be carbon monoxide poisoning, a gas leak, or suicide.

However, The New York Times reported, Mendoza said that Hackman, 95, and Arakawa, 64, were found in separate rooms, with one of their dogs dead in a kennel. But two other dogs were alive.

“Sheriff Mendoza said that there were no obvious signs of trauma to the bodies and that no note had been found,” the Times reported.

Further, the fire department and the gas company had confirmed it was safe to enter, seemingly ruling out carbon monoxide or a gas leak, at least by the time the wellness check was conducted.

“At this stage in the process there isn’t anything obvious like that,” Mendoza said. “The autopsy is going to tell us more.”

“We’re not going to guess this was an accident or natural causes,” he added. “It wasn’t typical.”

Director Francis Ford Coppola, who directed Hackman in his Oscar-winning role in “The French Connection,” wrote in an Instagram tribute, “Gene Hackman a great actor, inspiring and magnificent in his work and complexity. I mourn his loss, and celebrate his existence and contribution.”

Some of Hackman’s other memorable roles were in “Unforgiven,” “Bonnie and Clyde,” and “Young Frankenstein,” as well as comic book villain Lex Luthor in “Superman” and the title character in Wes Anderson’s 2001 “The Royal Tenenbaums.”

For many sports fans, Hackman’s turn as Coach Norman Dale in the 1986 film “Hoosiers” is a favorite.

“When not on film locations, Hackman enjoyed painting, stunt flying, stock car racing and deep sea diving. In his latter years, he wrote novels and lived on his ranch in Santa Fe, on a hilltop looking out on the Rocky Mountains, a view he preferred to his films that popped up on television,” the AP noted.

“I’ll watch maybe five minutes of it,” he once told Time magazine, “and I’ll get this icky feeling, and I turn the channel.”