There are intriguing similarities between a teenage hacker from Australia and the man behind WikiLeaks, the website behind the release of video with the power to upset the American military.

On the Al Jazeera television network on Monday, an overbearing British host interviewed Julian Assange, a founder of WikiLeaks - the online drop zone for whistleblowers.

Assange, who rarely makes public appearances and shuffles around the world with little more than a rucksack and a laptop, quickly dealt to his haughty inquisitor.

Lean and tall, with a handsome, distant face, long grey locks and dressed in deep blue shirt and dark suit with a blood red tie, Assange, in his late 30s, is a commanding presence. He has a deep broadcaster's voice and gave measured, drum-tight answers about the blow he'd just dealt the United States military with WikiLeak's release of footage of an American helicopter gunship killing Iraqi citizens and two Reuters journalists on a Baghdad street in July 2007.

The video, shot from the helicopter, includes the voices of soldiers urging a gravely wounded Reuters photographer to pick up his weapon (they apparently didn't realise it was a camera) so he can be lawfully finished off with the aircraft's deadly 30mm cannon; when a beaten-up van slithers to a halt and its occupants tumble out to aid the wounded. They, too, are gunned down. Only two maimed children survive.

It becomes clear why the military has resisted the demands of Reuters and others for the release of the video. The military long claimed it did not know how the Reuters journalists had died and it initially withheld the fact that children were present.

Assange resisted Al Jazeera's invitation to savage US authorities for their years of dissembling, remarking simply: "There was certainly spinning of the message and it does seem like there has been a cover-up."

He didn't need to say more: the video has been viewed an estimated six million times. Its impact on the reputation of US servicemen in Iraq is devastating. Another US military video - showing last year's bombing of scores of Afghan villagers as they siphon fuel from a tanker hijacked by the Taleban - is also coming to WikiLeaks.

Clearly somebody inside the US military has begun leaking - elevating WikiLeaks and Assange overnight from mainstream journalism's fringes to a must-see news-breaker.

"This is a whole new world of how stories get out," declared Scree Screenivasan, professor of digital media at New York's Columbia University Journalism School.

Yet for all its ideals in support of openness and freedom of information, those behind WikiLeaks - especially its key founder, Assange - dwell in shadows and intrigue. They have no headquarters, no offices and the barest formal structure. Assange himself is particularly elusive, part, obviously, through necessity and part through his mercurial makeup.

Home - the nearest he has to one - is said to have been eastern Africa for about two years. He has rarely spoken of his upbringing in Australia or his life outside his work, arguing that to do so may assist those who want him - and WikiLeaks - silenced.

BUT the trail of his life is across the internet. It is as coded and mysterious as the man he is today. It begins - publicly at least - in October 1991 when Julian Assange, then a teenager, is charged with 30 computer hacking offences. Prosecutors allege he and others hacked the systems of the Australian National University, RMIT and Telecom. They'd even managed to remotely monitor the Australian Federal Police investigation into their activities, Operation Weather.

Assange admitted 24 hacking charges and was placed on a good behaviour bond and ordered to pay A$2100 ($2700).

The police investigation in Australia began after an audacious attack on Nasa's computers in 1989. The word "Wank" appeared in big, bright letters on Nasa's monitors - an acronym for Worms Against Nuclear Killers. Underneath was an Australian connection - some lines from a Midnight Oil song. Whoever did it was never identified.

In 1997 an astonishing book was published in Melbourne. It sold a very respectable 10,000 hard copies but, when it was put on the internet free of charge, it was downloaded 400,000 times within two years of its appearance. Underground told the riveting inside story of the city's computer hackers, and Assange was a prominently billed in it as a researcher for the book's author, Dr Suelette Dreyfus, now an academic researcher. It opened with a detailed account of the Nasa attack.

Dreyfus wrote glowingly of Assange's pivotal role in her book: "Julian had worked thousands of hours doing painstaking research; discovering and cultivating sources, digging with great resourcefulness into obscure data bases and legal papers - not to mention providing valuable editorial advice."

The book did not name the Melbourne hackers but used their online identities and told their story.

The records of Assange's court case and his biographical details on WikiLeaks matched the story of Mendax - one of the hackers' online identities in Underground. In the book Mendax is described as a super-intelligent child who never knew his father and was dragged from state to state by his mother who pursued a series of turbulent relationships.

In 1988 Mendax was a 16-year-old living in Emerald, central Queensland - the age Assange was then. Dreyfus wrote: "For a clever 16-year-old boy the place was dead boring. Mendax lived there with his mother; Emerald was merely a stopping point, one of dozens, as his mother shuttled her child around the continent trying to escape from a psychopathic former de facto. The house was an emergency refuge for people on the run. It was safe and so, for a time, Mendax and his exhausted family stopped to rest before tearing off again in search of a new place to hide."

Dreyfus continued: "Sometime Mendax went to school. Often he didn't. The school system didn't hold much interest for him. It didn't feed his mind ... the computer system was a far more interesting place to muck around in."

She also wrote that Mendax had a deep voice for his age. Assange has a distinctively deep voice. Mendax fathered a son in his late teens. Assange has said he has a son attending university.

Mendax suffered a breakdown after he was arrested by the police and after a period in hospital he lived rough in the Dandenong Ranges outside Melbourne. When he finally appeared in court on the hacking charges, Assange was living in the Dandenongs.

Was this the story of Assange's life? Was he Mendax? Dreyfus will not say, citing the promise she made long ago to the young hackers who aided her with her book, that she would not disclose their identities. She is protective and still obviously close to Assange .

She told the Herald this week: "He is not politically motivated. He is more concerned with truth and the quest for it. He is certainly not party political. I think he sees that there are good people on both sides of politics and definitely bad people.

"He is a very brave person. He is convinced that it is worth taking high personal risks in exchange for getting truth out to the community."

Among WikiLeaks' volunteers, those who are close to Assange are similarly protective and reluctant to speak on the record. They described this week a man whose traits would not be unexpected if they evolved from Mendax's turbulent and nomadic formative years. Assange, they say, is noticeably self-reliant, self-contained, resourceful and apt to keep a distance from others.

After his conviction he stayed in Melbourne and built up his computer skills as a programmer and as a developer of freeware. He read widely about science and maths and is largely self-taught in most of his endeavours. He did enrol for a period at Melbourne University but did not complete his maths studies.

Less convincingly answered by those who know him is whether Assange's quest to reveal secrets is the destiny of man moved by social conscience. Or is the natural progression of a highly intelligent child, raised on the run, who found solace alone on a computer and the anonymous camaraderie of cyberspace?

For his epigraph in the online edition of Underground, Assange used an Oscar Wilde quote: "Man is least himself when he talks in his own person. Give him a mask, and he will tell you the truth."

Is Mendrax the real Assange?