It was 2002 and, after going through the fingerprint dust, statements from Russell Street bouncers and hours of CCTV footage, the then head of the Asian crime squad, Pat Boyle, reached a disturbing conclusion: Melbourne street gangs were becoming more violent and could no longer be ignored.

Two reprisals over three months, including the shooting of a 17-year-old who survived two bullets to the head only because a car windscreen slowed them, reinforced his view.

The first challenge was for the authorities to acknowledge there was even a problem. Today, says Detective Superintendent Boyle: ''Victoria Police is not in denial about gang presence.'' He admits it was different in the past. ''Yes, we were evasive, I think. But we're not now.''

The next step, Boyle realised, was to work out the parameters of a phenomenon whose boundaries remained indistinct at best. A gang could be simply defined as a group who identified with each other and were involved in criminality. But how did that definition fit Victoria?

Boyle set out to find the answers. In the 10 years since the Chinatown shootings, he has become familiar with the bloodthirsty Los Angeles-formed Mara Salvatrucha, the tattoo-faced Mongrel Mob from New Zealand and the US-wannabe gangsters found in London.

But what soon became clear was that none of those gangs explained what he was seeing in Victoria: groups who had formed because of government housing clusters in their neighbourhood, for example, rather than being born into gangs that had existed for decades, as was happening in California. The shape of these groups has also mutated over time.

Today, Boyle says, there remain issues with Asian and Middle Eastern gangs, forged after large-scale migration in the 1970s and '80s, who have now become major players in more serious crimes such as drug trafficking. There are also criminal groups who disappear as quickly as police realise they exist, described by Boyle as ''gang today, gone tomorrow''.

But of growing concern, he says, is the emergence of a new generation of gangs, often involving Pacific Islander or African youths, who, under a guise of robbery, bash strangers for kicks.

While that night in Chinatown was vicious, with both men narrowly escaping with their lives, at least the violence had an internal logic, albeit ugly. Last month, eight Islander teenagers as young as 14 were charged over a spate of robberies and bashings of taxi drivers. ''All you can put that down to is recreational violence,'' Boyle says. ''There's no reasoning behind it. The objective is to do what they wanted to do, steal an item. For them to still assault them afterwards just doesn't make sense.''

Local community leaders are also concerned. While some dispute the notion of organised gangs and object to the labelling of young people as gang members, they see an escalating problem. Abeselom Nega, who works with young refugees, particularly Africans, says he was recently shown Victoria Police data demonstrating that African and Pacific Islander youth are over-represented in the crime rates.

Pacific Islander community leader Ikani Taliai has already seen too many young people fall into street gangs.

''These kids see a gang as their new form of community. They don't fit into their parents' community and they don't fit into the Australian community. It's as simple and as complex as that,'' he says.

Taliai, from the United Pasifika Council of Victoria, a body designed to bring together registered Maori and Pacific Islander community groups, thinks some Islanders have already graduated from street crime to organised crime.

''It's reached a critical mass now. You can't ignore the fact that the focus has now been put on our communities for a negative,'' Taliai says. ''Because of these issues around violent crime, it's bubbled up. If it's left to fester, you will end up with serious organised crime.''

Boyle was awarded a Churchill Fellowship in 2004 to study Asian crime. To some youths, he says, the appeal of belonging - and being seen to belong - to a gang is clear. ''A gang leads to sex, drugs, rock'n'roll. It leads to things you wouldn't normally get access to.''

He hopes his research project will not only define street gangs in Victoria for the first time, but also help police stop their spread, both through providing better criminal intelligence and a foundation for community or proactive policing.

He has interviewed 35 Victorian police about their experiences for his Monash University master's thesis, to be completed in March, and hopes to speak to many more. Among themes he has identified are an obsession with US gang culture, from the wearing of the red and blue of feuding LA gangs the Bloods and Crips, to spraying 187 - the penal code for homicide in California - on walls.

The suburbs where gangs are most prominent, such as Footscray, Sunshine, St Albans, Broadmeadows, Springvale and Dandenong, have long battled with youth crime, partly, Boyle says, because they remain primary locations for the settlement of migrants and refugees. Their streets are filled with poverty, uncertainty and other youths in similar situations.

But it is also from these streets that solutions are growing, with police and community leaders coming together to try to tackle some of the causes of the violence.

Inspector Bruce Wemyss started a leadership program in Dandenong to teach young men how to keep themselves, and their peers, out of trouble. Many of his graduates are African and he is working on implementing the program with Pacific Islanders.

One of his graduates is David Jada, a Sudanese refugee who arrived in Australia in 2004. When a Sudanese teenager was stabbed to death in a Dandenong shopping centre car park last September, Jada helped Wemyss gather community leaders at the police station within hours.

It not only helped Wemyss provide important updates on the investigation, it drastically reduced the very real possibility of retribution. ''There are some boys that get in trouble, most of them don't get along with the police. There was no interaction with the police,'' Jada, 30, says. Now ''everyone from the leadership program tries to get police involved with the community and the community involved with police more''.

Boyle is optimistic about the potential of such programs. Not only will they attack many of the factors that cause gangs to form, such as isolation and struggles with identity, but they may halt the progression from street crime to organised crime.

Despite early intervention, he concedes some youths will inevitably graduate from crimes such as armed robbery into drug trafficking.

Even implementing these programs is not without risk: when Tasmanian authorities started a sporting club for disadvantaged kids in 2000, the time they spent together led to them forming a gang called the Glenorchy Mafia. It grew to encompass several families and remained linked to street crime for much of the next decade.

But Inspector Wemyss says the only unforeseen result of the leadership program so far has been that some youths have shown interest in becoming police themselves. ''We hope to develop some strong leadership in some of the more engaged young people which will see them work more closely with their peers.''

A complicating factor is that youth gangs are also turning on each other. Taliai, appointed as the Tongan representative on the United Pasifika Council because of his history of community work, says Islanders and Africans brawled so viciously at a recent 21st birthday party near Dandenong that several went to hospital.

This time the police response was telling. ''The police there jumped on it fairly quickly by engaging with community leaders. In the past, you would have the kids getting locked up and dealt with through the system. That brawl was an example of things that are happening all over Melbourne, but it was also an example of what is happening with the police. Sometimes this engagement is happening, sometimes it's not.''

Nega is the chief executive of iEmpower, an organisation that worked directly with 66 disadvantaged refugees last year, but he believes many more could have been saved from ending up behind bars at a cost of $180,000 a year. Were these thousands of dollars instead funnelled into his program, he has no doubt prison cells would empty. ''We run a program with very limited resources to do as much as we can to make sure these kids do not become criminals.''

That said, he does not believe young African men had become heavily involved in gangs. ''Gangs have leadership, structure, some kind of command system,'' Nega says. ''The sort of stuff that is reported to us is a serious concern, but it's not gang crime.''

Kot Monoah, a lawyer based in Sunshine who often works pro bono for those in the Sudanese community, thinks that alcohol or drugs rather than a gang mentality are to blame for any crime committed by a group.

He says those committing street crime have often either dropped out of, or been removed from, school. ''There is no support, and the next thing you know they become idle,'' Monoah says. ''And an idle mind is often a source of evil.''

Criminologist Greg Martin blames the media for the often hysterical reaction that leads to any group of young people being labelled a gang. Dr Martin, who has researched crime gangs in Britain and is now based at the University of Sydney, says Boyle's thesis, in an area short on research, may debunk those perceptions. ''If we can understand more at the grassroots level about youth crime and gangs, it can lead to better relationships with police and early intervention, rather than youth crime being such a politically charged issue.''

Boyle says perceiving gangs as solely the domain of migrants and refugees from Melbourne's down-and-out neighbourhoods is also misguided. He speaks about a former gang formed by well-educated white kids from the middle-upper class in Caulfield, who evolved to far more serious offending than their counterparts from poorer suburbs.

He also cautions against assuming Melbourne is awash with roaming posses intent on unbridled chaos. ''Yes, we've had some bad activities happening in Melbourne, but it doesn't mean we've got mayhem. Not even close,'' Boyle says.

''To the extent that there are absolute no-go zones, you can't compare the back streets of Melbourne to the back streets of LA. We'd be laughed at. They would think this is a sanctuary.''