Mr Acquaro, who was a confidant of a who’s who of Melbourne organised crime for more than two decades, has been named in the media as a police informer. Some reports have alleged Mr Acquaro was co-operating with law enforcement authorities as far back as 2008.
The truth of these allegations has taken on new importance following the launch of appeals against convictions for drug trafficking in the Court of Appeal by two major players in the tomato tins case, Zirilli and Madafferi.
Determining whether Mr Acquaro was a police source or ever provided information about his clients has been described as the “elephant in the room” by barristers Mark Gumbleton and Adam Chernok, who are running the Zirilli appeal.
The controversial issue was aired during a bail application for Zirilli in late September ahead of the Court of Appeal considering a challenge to his 2011 conviction and 26-year jail sentence on the basis his case was contaminated by Ms Gobbo and, potentially, Mr Acquaro.
“We say there is a very strong suggestion that [Mr Acquaro] was a registered informer and was so throughout this investigation, prosecution and subsequent appeals,” Mr Gumbleton told the court.
“We don’t say game, set and match – we say that is to be determined by this court.”
But Victoria Police is refusing to hand over information about Mr Acquaro that could conclusively resolve outstanding questions about his status, arguing the force never “confirms or denies” whether a person has been an informer.
Victoria Police has long maintained concealing the identities of informers is necessary to ensure their safety and protect the effectiveness of its intelligence operations. It routinely fights the release of this kind of information using what is known as a “public interest immunity” claim.
The decision to block the release of Mr Acquaro’s file comes even though Victoria Police lost a similar legal battle to block disclosure of Ms Gobbo’s informing history to her former clients. That case was argued and repeatedly lost on similar grounds, ending in a stinging condemnation of police by the High Court.
“The maintenance of the integrity of the criminal justice system demands that the information be disclosed and that the propriety of each convicted person’s conviction be re-examined in light of the information,” the full bench of the High Court ruled in 2018.
“The public interest in preserving [Gobbo’s] anonymity must be subordinated to the integrity of the criminal justice system.”
The High Court ruling upheld successive defeats for Victoria Police in the Supreme Court and Court of Appeal, with the 2½-year saga costing taxpayers more than $6.3 million in legal bills.
But new police Chief Commissioner Shane Patton appears to be prepared to re-litigate the issue, filing a similar public interest immunity claim to block the release of information it holds about Mr Acquaro.
At Zirilli’s bail hearing, Mr Gumbleton said his client opposed Victoria Police’s application because the same type of public interest immunity claim had already been definitively rejected by the courts.
“The Chief Commissioner [of Police] has form for making the production of these documents as difficult as possible,” Mr Gumbleton told the court.
“It’s not just Mr Zirilli, it’s not just Mr Madafferi. There are 32 people who have been convicted as a result of the tomato tins case, some of which – we don’t know how many – were represented by Mr Acquaro from the date of arrest through to the end of the process.”
Justice Mark Weinberg said the court had been “down this track many, many times before” and challenged Mr Gumbleton’s estimate the Acquaro public interest immunity claim could take up to two years to resolve based on the Gobbo example.
“On its face, it’s not the most complex of public interest immunity claims. For goodness sake, a court ought to be able to resolve that question of public interest immunity within weeks, not months, not years,” he said.
“The claims of public interest immunity in relation to Acquaro may or may not be significant so far as any application for leave to appeal. This is much simpler in lots of ways [than the Gobbo case]. It ought to be able to be resolved in a relatively short period of time.”
The DPP, on behalf of Victoria Police, told the court it expected the public interest immunity dispute could be resolved relatively quickly as there was already a “process underway”.
But the process appears to have hit an impasse, requiring the Court of Appeal to step in.
The court recently ordered the appointment of three independent barristers – known as amici curiae, or friends of the court – to review the Acquaro materials and challenge the police’s position on the public interest immunity claim.
The unusual legal manoeuvre is used to prevent conflicts of interest and the accidental or intentional disclosure of sensitive information.
The public interest immunity matters are scheduled to be heard later this month in a closed court.
Victoria Police declined to comment on its informer policy or public interest immunity claim because the matter is before the court.
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Chris Vedelago is an investigations reporter for The Age with a special interest in crime and justice.