New proof Cassie Sainsbury used as drug ring decoy

The Australian Federal Police is now investigating the Cassandra Sainsbury drug case with officers questioning her in Colombia.

There's new proof she was used as a decoy to a much larger smuggling operation.

A mystery man linked to an international crime syndicate operating in Australia could now hold the key to Sainsbury's freedom.

Behind the doors of a closed Colombian court room the explosive details were read out to a judge.

The mystery man 'Angelo' who Sainsbury claims supplied the cocaine does exist and authorities have linked him to Australia.

"The prosecutor is sure that this person is real, is a Colombian person and is in the country at this time," her lawyer Orlando Herran said.

He told 7 News 'Angelo' had visited Australia and China before returning to Colombia for the botched drug run.

In April, 22-year-old Cassie Sainsbury was caught at Bogota airport with almost six kilos of cocaine concealed with headphones.

But prosecutors believe she could have been a decoy while a bigger haul was smuggled through unnoticed.

• A special investigation from Colombia on alleged drug mule Cassandra Sainsbury

• Accused Aussie drug trafficker Cassie Sainsbury calls for financial aid as court day looms

• Accused drug mule Cassie Sainsbury claims phone evidence proves she is innocent

She was a pawn in a well-organised, international drug syndicate, according to her lawyer.

"There are people in Australia, there are people in Hong Kong, there are people in London and there are people in Colombia," Mr Herran said.

Seven News has revealed officers from Australian Federal Police interviewed Sainsbury behind bars in Colombia three months ago.

Her lawyer claims authorities are now investigating whether other Australians are involved in the syndicate.

"I don't know exactly but I actually think it's about 10 or 20 persons,"

In a statement, the AFP confirmed it is liaising with Colombian authorities but said it wouldn't comment on operational matters.

If 'Angelo' can be found before the case returns to court Sainsbury's lawyer believes she could walk free.

Without the mystery man, the six-year plea deal is her next best option.

The deal now being considered by a judge ahead of the Australian's next appearance on November 1.