IBAC inquiry: Justice Murray Kellam's recommendations into protected witnesses to remain secret

• Inquiry finds police mishandled key gangland witness

"As we know, there are known knowns; there are things we know we know. We also know there are known unknowns; that is to say we know there are some things we do not know. But there are also unknown unknowns - the ones we don't know we don't know."

This was a rather wordy statement made by the then United States defence secretary Donald Rumsfeld on Iraq. It also could have been made by former Supreme Court justice Murray Kellam in a small statement released on Tuesday over his inquiry into Victoria Police management of human sources.

Former justice Murray Kellam, who led the IBAC inquiry.Credit: JASON SOUTH

He undertook an inquiry for the Independent Broad-based Anti-corruption Commission but as it involves protected witnesses that could be killed, his report will not be released.

Which means this is a cryptic crossword with very few clues.

So first the known knowns:

• Kellam found police were negligent in handling certain key informers but their actions were not unlawful.
• The handling of the informers "had the potential to have adversely affected the administration of justice in Victoria".
• The Office of Public Prosecutions has been asked to review certain cases to see if the management of certain informers had an "adverse effect on any prosecutions".
• Two key informers, Terry Hodson (2004) and drug boss Carl Williams (2010) were murdered after they made statements to police.

Now the known unknowns:

• There is a truckload of court suppression orders out there, which makes it impossible to detail one particular informer who is the key to this inquiry.
• Police used that informer over some of the most sensitive investigations in Victoria. In some cases the matters remained private and in others they became very public.
• Kellam made 16 recommendations in his report but they will not be released.
• A series of defence lawyers claim some convictions could be overturned if a key figure is found to have perverted the course of justice.

Now the unknown unknowns:

• Police say they originally used the witness as a key insider and background source. Things went bad when the source was pressured to become a witness.
• The witness says there was no tampering with the justice system.
• Detectives say they did not encourage anyone to break the rules.
• Senior cops say there is nothing to point to any mis-trials.
• Some witnesses were allowed to run their own shows and manipulated police while others were pressured to the point of breaking down.

So what do we know?

• Cultivating, sustaining and protecting underworld witnesses is a dangerous business as most are acting out of self-interest.
• One left the protected witness program to become a paid hitman. Another was released early from jail on the promise of providing information only to turn rapist.
• One hid in a sleepy country town but became known as the "Mafia Guy" because he dressed like Al Capone and had bodyguards with him when he picked up a pizza - the appropriately named Sicilian Special (hot sauce optional).
• In every case judges warn juries to beware of underworld informers who testify as prosecution witnesses.

And with good reason.