Police investigating the deaths of Gene Hackman and his wife Betsy Arakawa are considering whether the Oscar-winning actor suffered a heart attack shortly before or after his spouse's sudden death

Blood tests revealed no presence of carbon monoxide in their bodies, leading investigators to reassess initial theories.

An investigator has now told reporters: "There is no immediate sign of foul play, although the lack of carbon monoxide has upended the initial theories about how they died.

"We are now looking at whether it could be a death followed by a suicide. Did Mr Hackman die suddenly from a heart attack and his wife was so distraught she took an overdose?

"Or could his wife have suffered an acute medical event which caused her death, and then Mr Hackman was in such a state that he had a heart attack and died? We are looking at all possibilities."

Gene, 95, and Betsy, 65, were discovered by a worker who arrived at the couple's £3.5 million ranch 26 February to carry out maintenance work.

Sheriff Adan Mendoza confirmed Gene's pacemaker had "abruptly stopped" and a preliminary analysis showed his last recorded event on 17 February.

He said: "A more thorough investigation will be completed, but both Mr Hackman and his wife tested negative for carbon monoxide."

Betsy was found collapsed in the bathroom with pills scattered on the counter and floor beside her.

The medications included treatment for thyroid issues, high blood pressure, chest pain, and a painkiller.

A space heater was found near her body, which initially led police to suspect carbon monoxide poisoning.

An officer close to the investigation said: "It may also be that Mrs Hackman had a medical crisis of her own. Mr Hackman was found in the mud room. She was 10ft or 20ft away from him in a bathroom. Did she try and get blood pressure medication or something like that?

"She could have had a medical incident which led to her death. The space heater was on the floor, suggesting she grabbed it and brought it down when she fell."

Police confirmed that while the deaths remain "suspicious," there is currently no indication of third-party involvement.

A full toxicology report is expected to take several weeks.