Former police chief Christine Nixon says she has faith that the relevant authorities will get to the bottom of Carl Williams' brutal murder.
Four separate investigations have been launched since the gangland killer was bashed to death in prison on Monday.
But the Victorian government is resisting calls for a royal commission into allegations of police corruption being linked to his slaying.
Ms Nixon said it has been a long time since she was a member of Victoria Police but she stood behind any decisions it made.
"I think whatever decision they make they'll deal with it properly," she told AAP on Thursday.
Under Ms Nixon's watch, Williams went on a murderous rampage to stay on top during Melbourne's bloody underworld war.
She said it was her biggest case but she didn't feel comfortable offering a further opinion on calls for deeper inquires on police corruption or a royal commission.
"I think that's for other people (to comment on). I'm long past those issues," she said.
"I really don't want to make any comments about Victoria Police and the operations. It's a while ago since I was there."
Williams' death has sparked concerns that another wave of gangland slayings will erupt, but Ms Nixon said she'll just have to wait and see like everyone else.
"I think you'd have to watch the signs to see if it's starting up again," she said. "I'd learn like you would."
Victorian Premier John Brumby said earlier that a royal commission wasn't justified because it would be "an unnecessary, wasteful and inappropriate use of taxpayers' money".
Instead, the police force's Taskforce Driver will examine the circumstances behind Williams' death while separate investigations will be conducted by the homicide squad, the state coroner's office and Corrections Victoria.
The police investigation will be overseen by the state's police watchdog, the Office of Police Integrity.
