Police could not stop lawyer-turned-informant Nicola Gobbo from giving legal advice to a client she helped arrest because she had "gone rogue", a police handler says.
The handler, known under the pseudonym Officer Sandy White, told the Victorian Supreme Court they tried to stop Ms Gobbo from speaking to her client, known as Mr Cooper, after his arrest.
They brainstormed ideas like sending Ms Gobbo to Bali so she couldn't attend the police station to give legal advice but she refused to participate, Officer White said on Tuesday.
She claimed she had to advise Mr Cooper otherwise she would be murdered because her role as an informant would be uncovered, he told the court.
"She said to me she would turn up (to the police station) whether I liked it or not," Officer White said.
He denied police wanted Ms Gobbo to be Mr Cooper's lawyer because otherwise another lawyer would "ask a million questions" and discover her role in his arrest.
Ms Gobbo instead had gone rogue and was out of control, Officer White said.
"She was certainly making her own decisions," he said.
Ms Gobbo later advised Mr Cooper to co-operate with police and give information about Tony Mokbel in exchange for a plea deal.
Mokbel was another one of Ms Gobbo's clients at the time of Mr Cooper's arrest in April 2006.
The drug king pin is trying to appeal drug trafficking and incitement to import charges he was sentenced for in 2012, arguing Ms Gobbo tainted his case.
Justice Elizabeth Fullerton told the court she found it "extraordinary" the police handlers could not control Ms Gobbo.
"By this date, she wasn't being managed as a human source - she was running her own strategy and running her own race," she said.
"There must have been a whole battalion of red flags in terms of her suitability to continue.
"Why wasn't this point a line in the sand that she could not be trusted?"
Officer White conceded police should have "deactivated" her as an informant but the risk to her safety was too high.
They did sideline her and place her in "babysitting mode" but it didn't make a difference, Officer White said.
"She came up with intelligence that couldn't be ignored," he said.
Mokbel was originally sentenced in 2012 to 30 years in prison for the drug trafficking and importation charges.
His jail term was cut to 26 years with a non-parole period of 20 years following a Court of Appeal decision in 2023.
Mokbel is now challenging the overall convictions, but Justice Fullerton needs to rule on several legal questions before a substantive appeal hearing can start.
The justice has been brought in from NSW to oversee the determination hearings, which are expected to run for 12 weeks.
