Cassie Sainsbury's fiance claims it was Australians who lured her into danger

Adelaide woman Cassie Sainsbury was allegedly carrying 5.8kg of cocaine concealed in her luggage as she tried to fly out of El Dorado International Airport in Bogota. Photo/Facebook

The fiance of accused drug mule Cassie Sainsbury has broken his silence to reveal how it was actually Australians who lured her into danger.

In an exclusive interview with Sunday Night, Scott Broadbridge also reveals more detail about the mystery man behind the deal.

Broadbridge has told journalist Denham Hitchcock his fiancee's flight to Colombia was a surprise to him.

In a teaser for the program which is due to air this Sunday, the program promises to reveal more about the mystery man behind the deal, a man Cassie has identified only as Angelo or Tom.

Broadbridge says he also saw payments related to the disastrous deal.

The couple were finally reunited after five weeks following Sainsbury's arrest at El Dorado International Airport at Easter.

Cassie Sainsbury's fiance, Scott Broadbridge, walks towards El Buen Pastor women's prison, shadowed by a crew from Channel 7's Sunday Night. Photo/news.com.au

Sainsbury remains behind bars in Bogota's El Buen Pastor prison, where she claims she is being bullied by other inmate.

Prison guards have accused her of lying and acting up for the cameras, a constant presence in Bogota since her arrest.

The South Australian maintains she was befriended in the Colombian capital by a mystery man who visited her at the hotel she was staying and made her an offer too good to refuse: 18 sets of headphones at bargain prices.

But inside those 18 headphone cases carried in her suitcase, airport police found 5.8 kilograms of cocaine.

Sainsbury says Angelo set her up and that she had no idea the cases contained illicit drugs.

Her incarceration has triggered a TV network battle, with Broadbridge doing an exclusive deal with Channel Seven's Sunday Night and Cassie's sister Khala and mother Lisa Evans signing with rival network Nine's 60 Minutes.

Sainsbury told news.com.au from inside prison last week it was her story to tell.