Mr Woods said it exposed a troubling culture in the force if raising concerns Ms Gobbo would be murdered was considered career-limiting.
“That shows a very, very deep problem with Victoria Police at the time,” he said.
Mr Biggin said in raising concerns with senior police he was not worried about his future in the force, as he had risen as far as he wanted to, but the careers of Ms Gobbo’s handlers.
“I was actually trying to … get [the handlers] to promote themselves so they were the next future leaders of this organisation,” Mr Biggin said.
“I was concerned for them that by standing up to the organisation and saying ‘We think you’re making this wrong decision in this’, for them their careers may well have a black mark against them.”
The royal commission is investigating the force’s management of informers, particularly their controversial use of Ms Gobbo, a former criminal barrister who gave police information about her own clients.
Towards the end of her time as an underworld source Informer 3838, then assistant commissioner Simon Overland drove the push to turn her from informer to witness in the disastrous attempt to bring down suspected corrupt cop Paul Dale, the commission has heard.
Mr Biggin and the human source development unit were worried turning her into a witness, which meant she would have to give public evidence in the court case against Mr Dale, would expose her role as an informer.
In the briefing note, the handlers said Ms Gobbo could be murdered and her role as an informer being exposed would lead to a royal commission and “perceived unsafe verdicts”.
The note went to the Petra taskforce steering committee, which was overseeing the investigation into the murder of another police informer, Terence Hodson, and his wife Christine.
Mr Overland, current Chief Commissioner Graham Ashton and current Assistant Commissioner Luke Cornelius were on the committee.
The committee didn’t heed the warning and Ms Gobbo was turned witness, secretly recording a conversation with Mr Dale that police alleged corroborated evidence from underworld figure Carl Williams that Mr Dale organised the hit on Hodson.
The charges against Mr Dale were withdrawn when Williams was murdered in prison and the precarious relationship police had with Ms Gobbo collapsed with her suing the force.
Tammy Mills is a Crime Reporter for The Age.