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.