It becomes clear why the military has resisted the demands of Reuters and others for the release of the video; the military had 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 the message and it does seem like there has been a cover-up.'' He didn't need to say more; by week's end the video had been viewed 4.8 million times. Its impact upon the reputation of US servicemen in Iraq is devastating. Another US military video - showing last year's bombing of Afghan villages as they siphoned fuel from a tanker hijacked by the Taliban - is also coming to WikiLeaks. Clearly someone inside the 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 Sree Screenivasan, a professor of digital media at the Columbia University journalism school in New York. 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 of a formal structure. Assange is particularly elusive, part obviously through necessity and part mercurial make-up. Home - or the nearest he has to one - is said to have been eastern Africa for the past two years or so. He has rarely spoken of his upbringing in Australia or life outside of 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, as coded and mysterious as the man he is today. It begins - publicly at least - in October 1991 when Assange, then a teenager, was charged with 30 computer hacking offences. Prosecutors alleged he and others hacked the systems of the Australian National University, RMIT and Telecom. They had 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 $2100. The investigation in Australia began after an audacious attack on NASA's computers in 1989.

The word ''WANK'' appeared in big letters on NASA monitors, an acronym for Worms Against Nuclear Killers. Underneath was an Australian connection - lines from a Midnight Oil song. Whoever did it was never identified. In 1997 an astonishing book was published in Melbourne. It sold a respectable 10,000 hard copies but, when it was made available free on the internet it was downloaded 400,000 times within two years. Underground told the riveting inside story of the city's computer hackers and Assange was 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 efforts: ''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 match the story of Mendax - one of the hacker's online identities in Underground.

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 16 years old and living in Emerald in central Queensland - the age Assange was at that time. 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.'' Dreyfus continued: ''Sometimes 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 teens. Assange has said he has a son at 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 to the young hackers who had helped her with her book, that she would not disclose their identities. She is protective of 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 absolutely 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 on background 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 programmer and as a developer of freeware. He read widely on science and maths - he is largely self taught in most of his endeavours. He did enrol for a period at Melbourne University but did not complete his studies in mathematics. 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 the natural progression of a highly intelligent child raised on the run, who found solace alone on a computer and anonymous camaraderie in cyber space.

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 Mendax the real Julian Assange?