The 22-year-old has now spoken publicly about her alleged crimes for the first time, giving an interview to 60 Minutes.
In a new clip for the upcoming interview, Liam Bartlett quizzes Cassie inside El Buen Pastor women’s prison - you can watch above.
He appears to be giving Cassie a grilling as she is asked "Whose idea was it? Whose idea was it to make a quick dollar out of carrying cocaine? How did you get here, who talked you into it?".
It comes just a month after a judge rejected Cassie's plea deal with Colombian prosecutors over drug smuggling charges.
Cassie agreed to reveal the identities of others in the drug ring to receive a lighter sentence of six years but today, the plea deal was officially rejected and she could be looking at 20-30 years in Colombian prison if she's found guilty.
"In the name of the Republic, and by the law, decides not to approve the agreement held between the prosecutors and the accused, Cassandra Sainsbury, with the help of the person who takes her defence according to what was exposed before," Judge Leon told a court in Bogota.
She claims she only agreed to smuggle 5.8kg of cocaine in her luggage after her family was threatened.
WATCH: Cassie Sainsbury is pictured smiling from behind bars. Post continues...
However, her plea deal was rejected as it conflicted with her initial statement and she's now due to stand trial on 26 September. She faces a maximum of 30 years in Colombian jail if convicted.
Immigration Minister Peter Dutton said Sainsbury’s case should serve as another warning to Australians travelling overseas.
"People need to abide by the laws of that country. If not, they will face serious consequences," he told Seven.
You can watch Cassie's interview with 60 Minutes on September 24 at 8.30pm on Channel 9.