From Left: Constable Monte, 1966; Jackie and Aristotle Onassis, 1975; Irian Jayan villagers encountered on the job, 1979; Below LA Photo Shoot.

"He used to do the worst divorce raids in the business," recalls investigator Lee. "He would crash through the window and take photographs [of copulating couples]. The guy used to think he was made of steel."

"At that time there were a lot of heavy-duty people in Sydney," says Monte. "It was a very rough period, lots of drugland stuff happening here. I was a young wog trying to get into a business when it was full of cashiered cops. The tough guy image was necessary."

Monte fell into the PI business after dropping out of law school and giving up a short stint as a policeman. The son of working-class Italian migrants with whom he did not get on, Monte was obsessed by the idea of becoming rich and achieving what his parents never could. It was to prove an obsession that has frequently guided him more clearly than his conscience.

While still in his twenties, Monte accepted the then-large sum of $8000 to fly to New York and kill a wealthy American banker. By sheer gruesome luck, it became his first big break. Monte took the money, although he claims to this day he had no intention of killing the man. However, while he was in New York pondering his next move, the banker's wife was killed in a freak car accident.

"After I gave the client the news there was a lengthy silence," Monte recalls. "Eventually he found his voice. 'My God, man,' he gasped. 'You couldn't get him so you got her.'" Word soon spread around Sydney that Monte was a ruthless hired killer. "This helped build my mystique," Monte writes. "In this game, a ruthless reputation isn't bad for a business."

His second, and biggest, break came two years later, in 1973, when he went to Italy to investigate an international pyramid selling scheme. While talking to businessmen in Milan, he was approached by a "smallish elderly man, wearing dark wraparound glasses and smoking a big cigar". It was Greek shipping tycoon Aristotle Onassis, who wanted to talk to Monte about the art of bugging. Onassis invited Monte to several lunches and soon he found himself in the employment of Greece's richest man and the second husband to Jacqueline Kennedy.

Monte was to bug the conversations of Onassis's business rivals. He recounts the story of how some Japanese businessmen were negotiating with Onassis to sell him turbines to drive his supertankers. They said $5 million was their lowest price. However, after the meeting Monte's telephone bugs picked up their phone call to Tokyo which revealed that their real lowest price was $2 million. "Next time they arrived at the villa, Onassis offered them a deal," writes Monte. "Two million, take it or leave it."

He also gained a firsthand glimpse of the more sordid side of Onassis - his constant spying on Jackie. "They were doing surveillance full-time on her," says Monte. "Bugging, breaking into her mailbox. The transcripts would come in. We knew exactly what was happening. "Often," he writes, "when he [Onassis] talked to me about her, it would be to complain: 'The sex isn't good anymore.' JAckie's visits [to Onassis's villa] all followed the same pattern. There would usually be a lunch or dinner at which they would remain relatively polite but unable to stop sniping at one another. Then there'd be sex. Not to Onassis's satisfaction, or course. For the duration of Jackie's stay they would catfight, and the tension would subside only when her car glided away down the drive."

At one stage, he says Jackie came to believe that Monte was a CIA mole planted in the Onassis camp in order to look after her. He recounts the exchange in his book: "He's a bad man - you must know that," Jackie said. Then: "Haven't you been told to help me?'

"But when I looked blank and said, 'No, who by?' she spat back, 'Don't play stupid. You Australians are supposed to be stupid but surely not that stupid.'

"They were two peas in a pod," says Monte, with the slightest flicker of a grin. "Neither was a particlarly nice person. She wasn't that clean herself - she was a bit of a ratbag. She decided to make as much money out of him as she could." She also had affairs, "but he didn't care that much, he cared about the money she was spending".

When I suggest to Monte that people may doubt his version of events, especially unprovable details of conversations that happened 30 years ago, he scowls. "It's a typical Australian feeling if they want to say that, that's why I moved to New York. There is this antipathy [in Australia] to anyone who's done anything."

The general themes of many of Monte's adventures have been verified by media reports at the time and by people who were there. It is known, for example, that he did work for Onassis, that he raised an army in Dubai, and that he went searching for Michael Rockefeller's skull in Jaya. But there is no way to independendtly verify much of what he says in his book. They are facts as he sees them, take them or leave them.