As the net tightened further around Osama bin Laden and his al-Qaeda network this week, one South Australian family's worst fears were realised when their son was captured by Northern Alliance forces while fighting for the Taliban. Their devastating news was compounded by the fact that he may now face the death penalty.

Immediately after the capture of David Hicks, a 26-year-old father of two from Adelaide, a complex picture emerged as to how an ordinary "Aussie bloke who liked to sink a few beers with his mates" found inner peace in the Koran before joining the Taliban, via a spell fighting Serbs with the Kosovo Liberation Army in the 1990s.

Some friends and associates, insisted he was a "decent guy" who must have been seriously misled in recent years. Others painted a different picture, of a moody loner with a sinister side who liked a fight, a man seriously damaged by steroid abuse.

Hicks grew up in Adelaide's northern suburbs but, never a good student, he dropped out of Smithfield Plains school when he was 14.

An old school friend, Jason Gray said the captured man's mental stability had not been helped by his habit of injecting veterinary steroids. "I've never actually seen him as a military person," Mr Gray said.

Hicks's own father dubbed him "Indiana Jones", such was his love for action and the wild, outdoors life. In his late teens he went to one of the most remote parts of Australia, on the Barkly Tablelands. There the locals remembered him riding at the local rodeo, working on cattle stations and in bars.

"He was scrawny looking. A young ringer looking for adventure," said one resident. In 1994 he returned to his native Adelaide where he fell for a local girl, Jodie Sparrow. The couple had two children but their relationship did not last.

But this week Hicks's former de facto rushed to his defence: "He's not the animal that everyone thinks he is," she told the ABC TV news.

"He's a caring person, he's just been misled by some persons I don't know of". From the time that relationship ended, the details of Hicks's life are sketchy. We know he spent some time training horses in Japan, then there is a gap and then, Kosovo, an experience most believe sent him completely off the rails.

It is not known what drove him to Kosovo but one former associate who spoke to reporters this week said Hicks was not an idealist. "I think he was in it for the money and the excitement," the source said. "He had gone through six weeks basic training [in Kosovo], he'd been in the trenches, he'd killed a few people, you know, confirmed kills, and had a few mates killed as well".

It also emerged he had approached the Channel 7 TV network three years ago offering to sell his story about his days fighting as a mercenary in Africa and in Afghanistan.

After Kosovo those close to him said he was a changed man. It was at this point in his life that he turned to the teachings of the Koran and converted to Islam. Then in 1999, seemingly anxious to learn more about his new faith, he moved to Pakistan. He was there just months before moving to Afghanistan. Wlai Hanifi, president of the Islamic Society of Australia, who knows Hicks well, confirmed this week that the young Australian had fought in Kosovo.

"He said he was involved in the fighting in Kosovo," Mr Hanifi told reporters. "He had come to the conviction that Islam was the true message and he wanted to become a true believer in Islam."

Now Hicks is a hate figure in his own country. His father said his son was "terrible . . . a terrorist".

For now he is being held hostage in Afghanistan by Northern Alliance fighters. He could be returned to Australia to face trial. Or he may face a court in the US where, if he could be linked to al-Qaeda he could face the death sentence.