Rumours and theories as to the fate of Sydney conwoman Melissa Caddick have swirled after her foot was discovered washed up on a beach several months after she vanished.

Following years of speculation, a top criminologist has now weighed in on the mysterious case with a theory on Caddick’s fate.

Dr Xanthe Mallett told The Daily Mail it’s difficult to determine whether Caddick is dead or alive given her severed foot is the only trace left of the conwoman.

“It’s possible, at the extreme end of what’s possible, in that what’s been recovered is a foot and medically you can survive without a foot,” she said.

“It wouldn’t be impossible to disappear when you have that much money. ‘As an investigator, I couldn’t rule it out. But what’s possible and likely are two very different things.”

Mallett ruled out one theory, telling the publication that “based on her personality profile I don’t think she’s likely to have committed suicide.”

“I think the most likely outcome is she was sadly murdered, second that she took her own life and third is that she’s still alive,” she said.

The new theory comes after Caddick’s husband Anthony Kelotti was recently served with a Personal Violence Order (PVO) in a motion to protect Isabella Allen, the Australian Securities and Investments Commission (ASIC) investigator examining his wife’s case.

According to 7News, the PVO comes as Koletti had allegedly sent Allen inappropriate text messages and engaged in social media trolling.

In an exclusive interview with  television programme Spotlight in October 2021, Koletti appeared to suggest it was Allen, and not his wife, who had turned him into a “victim.”

Caddick disappeared on November 12, 2020, after the Australian Securities & Investments Commission (ASIC) launched an investigation into the financial advisor for allegedly operating a Ponzi scheme.

A coronial inquest is expected to offer further insight into Caddick’s disappearance.