Elizabeth Jean Hackman told TMZ that the family suspects toxic fumes inside their Santa Fe, New Mexico, home led to the deaths of her 95-year-old father, his 65-year-old wife, and one of their dogs.

The daughter of legendary actor Gene Hackman believes he and his wife, classical pianist Betsy Arakawa, likely succumbed to carbon monoxide poisoning—though authorities found no evidence of a carbon monoxide leak.

However, authorities later stated that the circumstances were “suspicious enough in nature to require a thorough search and investigation.” An affidavit revealed that an “unsecured and opened” door was found at the residence, along with a prescription pill bottle and scattered pills near the room where Arakawa and the deceased dog were discovered. Despite these details, the fire department found no indications of a toxic leak in the home.

According to court documents, a maintenance worker, who hadn’t seen the couple in about two weeks, raised the alarm after receiving no response from inside. When authorities entered, they found Arakawa’s body in a mummified and bloated state.

Though there were no visible signs of trauma, Santa Fe County Sheriff Adan Mendoza said the couple’s deaths could have resulted from various causes, including double homicide, suicide, accidental death, or natural causes. Two surviving dogs were also found—one inside the house and another outside.

Forensic expert and Fox News contributor Dr. Michael Baden suggested the deaths were “typical” of carbon monoxide poisoning. He explained that if a car engine is left running without proper ventilation, carbon monoxide from the exhaust can seep into the house, causing both humans and animals to succumb without pain or awareness. He also noted that a boiler malfunction could produce the same deadly gas.

The couple had been married for over 30 years and had lived in their Santa Fe home since Hackman retired from acting in the early 2000s.

Following the discovery of their bodies, authorities applied for a search warrant and brought in the fire department and gas company to ensure the home was safe for further investigation.