Businessman David Campbell was used by his former mentor, squeezed by investigating police and now faces life in prison, his barrister says.
Campbell, 53, is accused of conspiring to import and possess a border-controlled drug and has pleaded not guilty to both counts.
He is standing trial in the NSW District Court alongside Tristan Waters, 40, after the pair were dramatically arrested in a Serbian hotel in January 2018 and extradited home following a globe-trotting undercover operation.
Authorities had allegedly found close to a tonne of pure cocaine, worth more than a billion dollars, concealed in steel beams from China inside a shipping container the previous year.
Waters has pleaded guilty to conspiring to possess a commercial quantity of an unlawfully imported border-controlled drug, but denies the import charge.
He did not give evidence during the trial but his barrister David Dalton SC told the jury Waters was playing the role of an expendable "heavy" standing in for a syndicate boss in Serbia, and had nothing to do with the importation in Australia.
Campbell was "marched" from the dock to the witness box for four days of examination, his barrister Ronald Driels said during closing submissions on Thursday.
"You have to decide whether you believe him or not," he told the jury.
Campbell and Waters were arrested along with Campbell's former mentor, Rohan Arnold, named as a co-conspirator in the same indictment.
The jury needed to carefully consider Campbell's evidence that he did not agree or know something illegal was inside the container, shipped through his company for Arnold and only sought to reclaim the container due to threats.
"It’s a real possibility, not absurd, not a fairytale, that Mr Campbell was used," Mr Driels said.
Campbell was a hard-working family man and army veteran, impressed by Arnold’s basic economics degree, and considered him a mentor after starting work for him in 2008.
"That mentorship can be seen as controlling in a lot of ways," Mr Driels said.
A former police officer gave evidence on the practice of "piggybacking", where reputable importers are exploited by organised criminals.
Campbell was a hands-on businessman who took efforts to recover what he thought was a missing shipping container, which had actually been seized by authorities, and did not attempt to hide his identity in doing so.
There was also evidence of the container being "repacked" in China, where Arnold has business partners, before being shipped to Australia, Mr Driels said.
Campbell was then caught in the middle as Australian Federal Police went on the hunt for "major players in an international syndicate".
"And if a little Australian citizen in the middle gets squeezed, so be it," Mr Driels said.
The AFP engaged in deceitful and manipulative conduct to "see what the ripple effect" would be, Mr Driels claimed, and watched and listened for more than six months.
They collected information to support their case which was selectively presented to jurors, asking them to draw illogical inferences from "dodgy facts", the barrister said.
Judge Phillip Mahony will direct the jury before it retires to consider a verdict.
