SMART, seasoned and knowledgeable about the criminal investigation system, Lee Henderson played the Queensland Police like a violin.

So convincing was he that a gaggle of detectives bent, broke and, eventually, shattered the iron-clad rules that stand between honest police work and outright corruption.

Described variously as a mafia hit man turned informant and a "super liar", he has been in and out of jail – mostly in – all his life. For the past 20 years he has been in prison in Queensland. He is currently serving two concurrent life terms.

On letterhead he generated himself in prison, Henderson describes himself as "Info Gatherer & Strategist, Freelance Operations Advisor, Recruitment Specialist".

In truth he was little more than a cunning killer, thief and conman.

Henderson took advantage of the methods some police, specifically officers attached to the Armed Robbery Unit, used to gather evidence.

He and others were given favours – time outside prison with their wives and other rewards – in return for information, little of which turned out to be of use.

The justification many of those police involved used for their behaviour was that the end justified the means, a mindset that a royal commissioner interstate once referred to as "noble-cause corruption".

But this attitude had a corrosive effect on the integrity of the police, and allowed criminals like Henderson to insinuate themselves into the lives of police.

It was also an attitude that fostered circumstances where the fund used to pay off informants, a fund to which banks and other financial institutions provided money to ensure results in robbery investigations, was misused by those police entrusted with it.

In several instances, the Crime and Misconduct Commission said, police took the money and then claimed it had been paid to informants.

In one case, officers even made an audio recording of a bogus payment to an informant, claiming it had taken place in a West End coffee shop.

The CMC and the Ethical Standards Command subsequently discovered that the recording was "highly consistent with having been made in proximity to car park bay 148 on level B2 of Police Headquarters".

Payments that did find their way to informants were approved with minimal checking of their bona fides. What records were kept showed payments of hundreds of dollars to people referred to as Jane Doe, Apprentice, and Fruitie, to name a few.

Following its investigation, the Ethical Standards Command recommended disciplinary action against five officers, the most senior of whom retired soon after.

The same attitude about the end justifying the means was behind the widespread practice of offering rewards and other inducements to prisoners in return for false information or even confessions about armed robberies. This is where Lee Henderson came into his own, and where the CMC found enough evidence of corruption to implicate a dozen police.

Operation Capri found Henderson had been taken from his cell at Wolston Correctional Centre no fewer than nine times.

Prisoners are supposed to be taken from custody in this manner only if police suspect they have committed a crime.

The first time he was sprung from his cell, in February, 2002, records show Henderson wanted to talk about an offence the previous month.

The problem was he had been in jail for the past 15 years.

None of the paperwork that was supposed to officially record this episode was completed.

On one of the next eight occasions in which Henderson was able to walk out of his jail cell with police help, the excuse was that he was helping them solve armed robberies or homicides.

It turned out that at least one of these crimes never took place. There is also evidence Henderson was allowed to roam around Brisbane unaccompanied and that he boasted in letters about how police were "feeding" information to him about investigations.

On one occasion, Henderson was taken to Brett's Wharf restaurant precinct in Brisbane, in civilian clothes and wearing a police tie, to meet a woman friend and her family.

On another, a prison officer saw him lunching with a police associate at the Sands Hotel, Cleveland.

Henderson's success at manipulating circumstances for his own ends grew, to the extent police began illegally diverting phone calls he made from prison.

In all, he made nearly 1500 phone calls from prison this way over three years, half to other law enforcement agencies, the rest to family, friends and criminal associates.

This set-up enabled him to arrange for the theft of a sports bag containing up to $250,000 in drug cash, and organise a bogus drug raid to cover up the theft. Then the payments to his police associates began. Thousands of dollars worth of cash, cars, even baby clothes.

By the time he was moved from Wolston to Rockhampton, there was nothing noble in Henderson's relationship with his police associates.

He was able to tip off the subject of a criminal investigation, get charges against another criminal associate dropped, and even convince police to access computer records for his own purposes.

The coup de grace was a $5000 reward he got for help in solving crimes – help he never delivered.

Operation Capri took 2½ years, tens of thousands of exhibits and interviewed 200 witnesses.

Twenty five officers were caught in Operation Capri's net, and most of those swallowed Henderson's con – hook, line and sinker.