A small shared Bankstown apartment, an old sedan, a job as a waiter and dole payments – such was the meagre world of Vietnamese refugee Pete Tan Hoang.

Except, that is, for as much as $1 billion he gambled at Australia's biggest casino, Crown Melbourne, in a little over a decade.

Hoang, 36, was shot in the face in September while waiting on a darkened street in suburban Sydney.

His murder has left police perplexed, but has also shone a light on massive laundering on behalf of a global crime syndicate with links across Asia and the Americas, and highlighted the scale of the narco money laundering problem in Australia.

Hoang's story, his rise from a Vietnamese-born orphan living on a refugee visa to one of Australia's biggest gamblers and money launderers, also raises concerns about how he was able to rort the system for so long and for so much money – particularly at Australia's biggest casino.

Court documents from a recent case reveal Hoang ran as much as $1 billion in black cash through Crown between 2000 and 2012.

He also was allowed to gamble under four different names and received a slew of perks, including overseas holidays, cash gifts of as much as $100,000, and gambling "commissions" in the hundreds of thousands of dollars.

The Australian Crime Commission (ACC) estimates at least $15 billion a year is laundered in and through Australia each year; other estimates suggest it is higher.

Much of that money is the result of drug trafficking.

Space to play or pause, M to mute, left and right arrows to seek, up and down arrows for volume. Watch Duration: 9 minutes 9 m How did this man launder nearly $1 billion through Australia's biggest casino?

Most federal crime agencies in Australia acknowledge they face an increasingly monumental struggle against global crime groups seeking to launder their multi-billion-dollar narco profits.

Despite being targeted during a 2005 to 2006 ACC operation dubbed Operation Gordian, and with a series of intelligence reports revealing his role as a drug trafficker and money launderer, Hoang remained a fixture at Crown until he was charged with money laundering in late 2012.

Hoang was also involved with several Vietnamese-Australian drug trafficking syndicates in Sydney and Melbourne.

New South Wales Police homicide squad commander Mick Willing told ABC's 7.30 and Fairfax there was little doubt Hoang's background in drugs and Asian organised crime syndicates played a role in his death.

"We have certainly considered that he was involved in drug trafficking and moving money through casinos - [that] may have been a catalyst for his death," Mr Willing said.

How a Vietnamese orphan wound up in a global crime syndicate

Orphaned at a young age and raised by foster parents, Hoang arrived in Australia in 1997 on a student visa and an Indonesian passport under the name Petrus Keyn Peten.

Within months he had applied for refugee status, under the name Minh Tan Nguyen.

By 2001 he had become an Australian citizen, and changed his name twice more.

By the time he had become a citizen he had already been banned from Sydney's casino, The Star.

Law enforcement officials speaking to 7.30 and Fairfax on condition of anonymity said he became a professional money launderer, gambling millions in the profits of heroin and other drugs, giving it the appearance of legitimate casino winnings.

Intelligence gathered by state and federal law enforcement during the mid 2000s suggests Hoang was involved with a group of Vietnamese-Australians that formed the Australian end of a Hong Kong-based crime group known as Ong Ngoai – or "grandfather" in Vietnamese.

Ong Ngoai is a global drug trafficking syndicate with links across Asia and North and South America. Australian police have identified at least two dozen drug syndicates here with links to it.

Michael Purchas was the brains behind Operation Gordian, and spent months watching Vietnamese-Australian criminals including Hoang sell drugs and launder the profits.

Hoang's exclusive treatment at Crown Business class flights from Sydney

Business class flights from Sydney A villa in the Crown Towers

A villa in the Crown Towers Free food and alcohol

Free food and alcohol Cut of gambling turnover

Cut of gambling turnover Minimum $1 million buy-in

"He was a known gambler at casinos, [Hoang] would certainly deal with other people's money at casinos under instructions," Mr Purchase said.

Operation Gordian was hailed as a breakthrough investigation into money laundering and resulted in the convictions of small group Vietnamese-Australians responsible for laundering about $93 million in drug profits in a year.

At the time Hoang was only a peripheral figure and managed to slip the police dragnet.

He continued to be involved in the trafficking of heroin and other illicit drugs. The amount of money he laundered through casinos – primarily Crown Melbourne – also increased.

In May 2012 Hoang was once again banned from Sydney's Star and also from Jupiter's Casino in Brisbane.

His luck ran out in October 2012, when he was arrested in a high roller room at Crown casino attempting to gamble with $1.5 million in cash that police alleged were the proceeds of crime.

Twelve years of gambling yielded almost $1b, court case hears

The resultant court case revealed he had bought about $75 million worth of chips at Crown between 2000 and 2012, which equalled a gambling turnover of at least $225 million, possibly as high as $1 billion.

Deakin University social scientist Professor Linda Hancock is the author of a book on Crown casino and said Hoang's turnover was an "amazing" amount of money.

"He would be accounting for a very high proportion of gambled funds. He would be what's called in the business, 'a person of interest'," Professor Hancock said.

"So you would think that there would be a trigger between any casino and the police for such a person."

While Crown did report many of Hoang's transactions to federal authorities as it is required to, it also provided him a slew of perks and benefits not available to most gamblers.

He was allowed to have four different identities at the casino – Pete Hoang, James and John Ho and Patrick Lu – and received free business class flights, accommodation, and alcohol as well as cash gifts up to $100,000.

The case also revealed his remarkable gambling patterns.

A hearing in June this year received evidence that during the month of September 2012, he was bought over $9 million in chips and played the card game baccarat at an average of $106,000 per hand.

The casino paid him a commission based on the amount he had gambled, and that month he earned $199,000 as a result of his high-stakes gambling.

Crown casino declined to answer specific questions about Hoang's treatment, but said: "Crown is and has been for some time assisting state and federal law enforcement agencies regarding Mr Hoang and we will continue to do so."