Gene Hackman's health was "really slipping" in the months before his death, according to family friends

Speaking to People, Daniel explained that Hackman was "essentially kind of home-bound" and Barbara confirmed that the Oscar-winner had "quit riding his bike through the neighbourhood" around a year ago.

Aaron revealed that Betsy had been doing her best to keep her husband "active and engaged".

He said: "Betsy tried to keep him kind of active and engaged. She was still trying to keep him as active and engaged and as healthy as possible."

Aaron - whose family had known Gene and Betsy for over 30 years - explained that the pair "were one of the tightest couples I've seen".

He said: "They seemed like real life partners, really, really close to each other, and they were both incredibly kind. And they were reserved, but they were real, (and) a lot of fun."

Barbara added: "Gene was as proud of Betsy as she was of him. She had been a concert pianist. Over at their houses, she had a special building, a studio that half of it was her grand piano (and) another half was Gene's art studio."

Investigators have suggested that Hackman was likely to have been dead for nine days prior to the discovery of his body as his pacemaker was last operational on February 17.

Santa Fe County Sheriff Adan Mendoza told reporters: "I think that is a very good assumption that that was his last day of life."