The Age reported that gestures had been exchanged on court video links while proceedings were adjourned, but their meaning was unknown.
"The sign language becomes part of the crew, so they're all on the same page. They generally do that sort of shit if they think they've been bugged or, you know, watched or listened to," a former organised crime figure told The Age. "It just looks sophisticated because you haven't seen it before. Everyone's got their signs on what this sign means and what that sign means among each crew."
The language is not Auslan, the official Australian sign language. Corrections Victoria does not offer Auslan courses in prison. Instead, it is a bespoke, one-off language with gestures that vary between crews. "One might put three fingers up instead of two fingers and a thumb for the same thing. And people think, 'What the f---'s that?' But no one knows but me and you, basically," the informant said.
The Age said some gestures appeared recognisable, but reported that authorities could not determine their meaning.
Similar secret communication has been documented in prison visits and on the street. In 2017, authorities recorded visits involving jailed gangland figure Kazem "Kaz" Hamad and his brother, but could never decode the conversations. An associate who later became a prosecution witness testified: "In every single visit when they talk, it's not like plain normal English, it's more like, you know, gestures, you know, they use code. ... I didn't know what they were talking about half the time and I just kind of played along."