A murder plot was thwarted and drugs and weapons were seized in a police crackdown on a Melbourne-based organised crime syndicate.
Victoria Police Acting Deputy Commissioner Bob Hill said officers arrested and interviewed two men from the crime ring over a conspiracy to murder, although no charges have been laid.
Mr Hill said police received credible information on Friday that members of the syndicate, including people currently in custody, were planning to commit murders by the end of the weekend.
The accused head of the crime ring, 33-year-old George Marrogi, was this week charged after allegedly ordering associates to import drugs while pretending to call his lawyer from prison.
Marrogi is currently in Barwon Prison awaiting sentence for murder.
Mr Hill would not say whether Marrogi was one of the men questioned over the conspiracy to murder allegations.
But he said 30 people were charged in the crackdown, which also led to the seizure of illicit drugs, firearms, and cash.
"While the results so far have significantly disrupted this criminal criminal enterprise, we all recognise that work is far from over," Mr Hill told reporters on Wednesday.
"This investigation is a demonstrable example that no individual or group is beyond the reach of law enforcement. We will hold you to account.
"This has been a day of reckoning. In fact, I expect this operation will result in some individuals spending the rest of their days in incarceration."
Mr Hill said the joint investigation between Victoria Police and the Australian Federal Police was ongoing, with more charges expected to be laid.
AFP Assistant Commissioner Krissy Barrett said the arrests should serve as a warning to criminals.
"If you're facilitating drug importation into Victoria, whether you're doing it from a local jail cell or from offshore, we will identify you and we will stop you," she said on Wednesday.