Cassie Sainsbury: US Tip-Off Led To Arrest

Turns out it was a tip-off from America's Drug Enforcement Agency that led to Colombian authorities searching Australian woman Cassie Sainsbury's luggage, as she tried to leave Bogota Airport last month.

They put the Adelaide 22-year-old on an alert list after picking up on red flags, including the purchase of her ticket to Colombia: it was made last-minute, by an unknown party in Hong Kong.

Bogota Airport's head of narcotics, Colonel Rodrigo Soler, has told The Australian there are a few other ways Cassie "fits the profile".

"When someone leaves their country for Colombia without a strong justification - for instance if a person comes to Colombia for two or three days - that triggers an alert," he says. 

"If a person doesn't have much money, is young and travelling alone, that information is sent to us so we have that in our control points.  Nearly always the captures we get are from this kind of intelligence."

Though he admits her claim she was tricked into packing the drugs is not impossible.  He says about 10 percent of people really don't know what's going on when they're arrested.

Cassie is now in prison awaiting her trial in two months' time.  She's been given legal advice that pleading guilty will reduce her sentence.