At first, only ambient sounds crackled from the little speaker: a breeze in the grass stalks; a tree heat-flexing; a crow cawing. Then Hansen’s voice emerged: slow, reedy, a man becoming weak.

Denise Rennie, he said, was a New South Wales police civilian analyst working with Federal Police and Vita Roesch and other Major Crimes detectives on a large-scale arms and drugs smuggling ring comprising immigration agents, bikie gangs, Border Force officers and bent police. Along with the smuggling there were ancillary crimes including extortion, bribery and money laundering.

At the midpoint of the investigation, an attempt was made on Rennie’s life—she was shot at by a motorbike pillion passenger—and the family was placed in witness protection near the town of Moree, in northern New South Wales, until the trials.

Six weeks later her husband, Neil, was shot dead at home.

Normally he’d not have been there—he worked part-time for the shire—but he and the older girl, Louise, were home sick. Louise witnessed the shooting and recognised the shooter as her mother’s work colleague, Vita Roesch. She escaped from the house with a mobile phone and called her mother, who was out shopping with the other children.

The family fled. They made no contact with anyone for eighteen months. ‘Except,’ Hansen said, slurring his words, ‘Denise made a classic angry-idiotic move—she called Roesch and told her she was going down. You could say Vita was highly motivated after that.’

Roesch, a major player in the very crime ring she was investigating, was in a position to manage the flow and storage of information. She’d have known when Denise Rennie was getting too close.

‘Then back in October,’ Hansen said, ‘Denise made contact with us.’

She was cagey and she was patient: started with untraceable thirty-second calls from public phones to her dead husband’s Dog Squad friends. Quick, in-and-out questions, random times of the day and night, until she reached Hansen’s boss and decided she trusted him. Hirsch imagined those calls: she must have driven all over the state looking for phone boxes.

‘The money was running out and she was lonely I guess, and sick of living out in the sticks and worried about her kids’ futures,’ Hansen said, ‘but mainly she was pissed off about something she’d read online.’

Her old case, adjourned when she disappeared, had been reopened in a watered-down form: minor charges only, against a handful of baggage handlers and couriers. What about the main players? What had happened to all that evidence she’d gathered?

‘Vita Roesch happened to it,’ Hansen said. He coughed, spat, groaned.

Then Denise had dropped her bombshells. Not only had she saved some of that evidence to cloud storage but her daughter could ID Roesch as the shooter of her husband.

‘The boss set up a team to investigate Roesch. Small, hush-hush.’