Protected witnesses become the weapon against the big fish

But there's a problem if the star witness is in love with his own gangster image and insists on collecting his takeaway pizza dressed like Don Corleone.

In a town where cargo pants pass as semi-formal, cashmere overcoats draw attention. In this case, so did the two stone-faced men who seemed to be full-time minders.

Soon, the man who had a secret witness protection codename was the talk of the supermarket and too many locals worked out his real identity.

It didn't help that his name was daubed on a busy road overpass. It was Victoria's worst-kept secret underlining the difficulty police have in "hiding" anyone whose name or face might be known.

Police are increasingly using protected witnesses to spear the big fish of crime. And it is usually a dirty business.

The system is not set up for innocent witnesses good folk who stumble on to a crime and are then willing to do their civic duty. They go to court every day, testify what they have seen and then go home.

Most protected witnesses are criminals offered deals to "give up" bigger prey in the underworld food chain.

One of the most valuable was the robber turned hitman dubbed "The Runner", who worked for the late and lamentable Carl Williams, a drug dealer with delusions of power.

The Runner was an old-school crook who stayed silent until he realised he would spend the rest of his life in jail unless he delivered Williams's head figuratively, at this point.

But when Purana taskforce detectives secretly took him from prison for talks, he realised that Williams had used him. So, over a month, he exposed in detail Williams's involvement in a series of gangland murders.

When asked what he wanted in return, he said he fancied a reduced sentence and a vanilla slice. He got both. It was the first time in Australia a professional hitman was allowed to cut a deal and it proved to be the icing on the cake against Williams. Faced with The Runner's testimony, Williams pleaded guilty to three murders (he was convicted of a fourth) and was sentenced to a minimum of 35 years.

Now police are busy trying to "turn" convicted (or soon to be convicted) offenders with offers they can't refuse.

One convicted murderer has been offered sweeteners including a reduced sentence, an annual subscription to The Age, a signed set of true-crime books and a box of steak knives (to be redeemed outside prison), in exchange for a statement implicating a colourful industrial relations expert and author in a series of murders. The man has declined.

Offers were made to try to turn Carl Williams. He was removed from prison and was allowed to spend time with his father, George, who was also behind bars. Williams, it is said, bragged to select inmates that as an added inducement he had been allowed to spend some quality time in the company of two prostitutes in a motel room.

One of the inmates must have been less than impressed by this as he is the man who allegedly killed Williams with a piece of an exercise bike in Barwon Prison.

Self-motivated informers make for murky waters in criminal cases.

Investigation of the murder of the "vampire" male prostitute Shane Chartres-Abbott began when a career criminal came forward and volunteered that he was the killer.

He didn't have a guilty conscience he just wanted to implicate a serving and a former detective in the case, thereby giving himself some bargaining chips.

The hitman quietly pleaded guilty to the murder in March 2008, confessing he was the shooter and naming his co-offender as Evangelos Goussis. As Goussis is serving life over two underworld hits, he is hardly in a position to argue that his feelings were hurt by the claims.

The killer pleaded guilty but his concurrent sentence meant he was not going to serve any extra jail time. It was a free hit. He is eligible for release in 2023.

The serving and former policemen that the informer named as murder conspirators say he is lying. Investigators believe he is telling a version of the truth.

Meanwhile, the second member of the alleged hit team refuses to talk to police in other words, Goose won't cook anyone. And so the case remains stalled.

Defence lawyers say co-offenders act out of self-interest and embellish (or fabricate) their stories to save their own necks.

Prosecutors say one of the only ways to crack gangland cases is to use the corroborated evidence of insiders.

But the system seems to struggle when the insider is not a co-accused.

Which brings us to the case of Nicola Gobbo the passionate defence lawyer.

Her police critics (and there are many) claim she became personally involved with some of her clients. So it was a shock when it was revealed she had changed sides and worked as a police double agent.

Gobbo wore a tape and recorded former drug squad detective sergeant Paul Dale making possibly incriminating statements over the murder of police informer Terry Hodson, killed at his Kew home, with his wife, in 2004.

Dale was arrested but last month the charge was dropped.

He says he can now get on with his life. Gobbo can't. Her career and her health have been ruined, and her future remains uncertain.

She has been difficult to deal with and has refused to enter witness protection. Police, on the other hand, have failed to show the required flexibility to deal with a vital but high-strung witness.

Now Gobbo is suing police. The case will be ugly unless cooler heads settle it first.

There have been repeated efforts to nobble star witnesses.

Wendy Peirce was the jewel in the Crown case against four men charged with the 1988 Walsh Street murder of police constables Damian Eyre and Steven Tynan until she changed sides at the last minute and derailed the prosecution case.

Gangster Alphonse Gangitano paid for two witnesses to skip the country when they implicated him in the 1995 murder of Greg Workman. The case against him was withdrawn.

But sometimes karma has the last word.

There was the murder suspect who jumped on the same tram as two witnesses he had seen talking to police. He took them to a safe house where he threatened and intimidated them into changing their stories.

The case collapsed and the suspect headed to the warmer climes of northern NSW a free man.

Then one day his modest tin dinghy sank after allegedly striking a giant sea turtle. His body was found floating agonisingly close to a buoy that should have offered him some chance of survival.

Which proves that while justice may be slow, it is sometimes hidden just below the surface.

And it has a hard shell.