For decades the infamous gumshoe has been the bane of a profession which already struggles against the common view that it's occupied by slightly shady characters, loitering in shadows in the pursuit of other people's dirty little secrets. What is scandalous is that the 66-year-old publicity-seeking rogue continues to operate despite the endless complaints to police and consumer affairs watchdogs. Over the past 15 years NSW Fair Trading has received 43 complaints against Monte and his associated companies. Over the same period, there have been 44 complaints about companies and private investigators trading in other names but which are in fact Monte. Between 1999 and 2001 the Fair Trading Tribunal handed down seven judgments against him, all undefended, for amounts ranging from $700 to $10,000 - money that Monte had taken from clients, for work which was either not done satisfactorily or not done at all. In 1988, the then consumer affairs minister issued a public warning about ''Frank James Adam Monte, trading variously as Australian College of Private Investigators, A. A. Adrian and Sons, the Monte School of Investigations, and Tonti Security.'' Consumers were told to avoid Monte, who took clients' money but did not do the work. He ''demonstrates a contempt for his customers which should be exposed in the public interest''. Almost 25 years after that first public warning, Monte is still at it. He still takes thousands of dollars and fails to do the investigations, then abuses and threatens his clients when they complain.

Take John, who rang the Melbourne office of Parker Taylor last year. The man who answered ''raspingly told me his name was 'Mark Strong', and gave me a quote for doing some investigative work''. Several thousand dollars were required as his team of 40 investigators would be needed, said Mr Strong. Five weeks later, Mr Strong wanted more money. When John called what he understood to be the Melbourne office once again and asked for a progress report before paying any more money, Mr Strong hung up. After repeated calls were not returned, John threatened legal action. So Mr Strong emailed in reply: ''You do that, you f---ing little c---! You go ahead and take legal action, and I'll take action against you for wasting my f---ing time! I'll come to your house at 3.00 am and make your life a f---ing misery! Now don't call me again you f---ing little c---!'' Imagine John's surprise when he rang the Sydney office to complain, only to find Mr Strong answering the phone. An hour later he was even more surprised when the same Mr Strong answered the firm's supposed San Francisco number. When asked about his alleged use of aliases this week, Monte said he had ''never'' personally used an alias but had employed other people, such as ''contractors'' to occasionally do work on his behalf. And Mark Strong? ''He worked part-time with me for five minutes. What's he got to do with anything?'' Mr Strong crammed a lot into those five minutes. Mark Strong is listed on corporate records as the person running Red Velvet Models, an escort agency which belongs to Monte's fiancee, Sharon Sargeant. Red Velvet Models' website says it's a ''professionally managed business providing discrete liaisons''. Mr Strong also seems to live in the very same Darling Point apartment as Monte and his fiancee.

Another person who alleges she was scammed by Monte last year paid $1500 to Spybiz for telephone equipment. When no equipment was forthcoming and Harry Lime Orson demanded $4500 more, the woman began her own inquiries. Her money had gone into an account operated by Sharon L Sargeant, of Thornton Street, Darling Point. The account name: Red Velvet Models. Harry Lime Orson has never run a business and is not any electoral roll in Australia. Harry Lime was the fictional character played by Orson Welles in the 1949 thriller The Third Man. Asked if he knew Harry Lime or Harry Lime Orson, Monte said, ''Who's he? Never heard of the man.'' Later he maintained he had ''too many people work for me over the years, so I'm sorry but if we're gonna start talking about some bloke here and there, I'm not likely to remember everyone''. When the woman who ordered the phone equipment accused Harry L. Orson of being a front for Frank Monte, she received the following email: ''You stupid idiot I hope u know I do far saved ur ass by not informing Mr Monte of your insults. Mr Monte resides in LA and was arrested several times for attempted murder as well as running mercenaries on the Arabian States. Do it's self a favor as neither he nor I live in Australia and piss off before things get bad for u. Ps no one lives at Thornton Street. You are now blocked. Harry.''

At least some of ''Harry's'' email was true. In 1989 Monte was acquitted of soliciting someone to murder his first wife, Erin. The alleged plot to murder Mrs Monte by electrocution in April 1984, involved dangling live electrical wires from the ceiling of a garage where she was to park her car. The case collapsed as the evidence of the key witness was found to be ''unworthy of belief''. When The Sun-Herald asked, ''Have you ever killed anyone?'', Monte paused before replying, ''No comment.'' Last year, another client, Val, suspected her husband was cheating. A Richard Clark from Parker Taylor gave her the choice of three bank accounts - Morgan Turner, Parker Taylor or Mason Steele - for the $3500 to ''locate your husband by confidential means, and watch and observe him for as long as a week or so to see if he is being unfaithful''. Val was horrified when her inquiries were greeted with a torrent of abuse - and threats to tell her husband and his girlfriend. Her suggestion that the detective agency's staff were ''bogus'' was met with the following reply: ''We do not want to talk to you you have proven to be a foul mouthed and incredibly stupid woman who will not listen … You owe us now $800. If we don't get that by Monday night we will issue a summons and serve you. Mr Strong'' A decade ago, the Federal Court Justice Brian Tamberlin described Monte as ''deceitful''.

In his memoirs, The Spying Game, which later became known as The Lying Game, Monte concocted a connection with the late fashion designer Gianni Versace. Exploiting the huge media attention in the wake of the fashion designer's 1997 murder in Miami, Monte had claimed that he had been working for Mr Versace and that his client had been murdered by the Mafia. The Versace family was outraged. ''These were a wickedly false set of assertions … The evidence clearly demonstrates that Mr Monte feeds on the oxygen of self-generated publicity and creates occasions for it,'' the family's barrister Henric Nicholas, QC, told the court. Justice Tamberlin agreed. When Monte did not pay the $400,000 in costs that were awarded to the Versaces, the famous fashion family bankrupted him. In 2007 there was yet another public warning over Fairchild Kirby and Kennedy Marshall, two of the firms in the Monte group. According to the Australian Securities and Investments Commission, Fairchild Kirby used false names when dealing with prospective clients, requested cash payment up front, then did not perform. ''He should be called Frank Monster,'' suggests another of his latest alleged victims, Susan Pintos, an animal trainer.

In 2010 Ms Pintos paid Parker Taylor $2750 to find the woman who had taken her white miniature trick pony. She later discovered that her money had gone into Frank Monte's account. When she demanded her money back, she was accused of being ''an ignorant and rude woman'' and that if she continued with her ''asinine assumptions and defamatory statements'' she would be sued. Complaints to the local police, the licensing squad, to the small claims tribunal, where Monte failed to turn up, got her nowhere. In August last year she complained to the Security, Licensing and Enforcement division of the NSW police which deals with private investigators. Loading ''I am disgusted that Frank Monte continues to prey on the vulnerable and trick people out of their hard earned money and that I have had to become yet another of his victims. Why isn't there anything being done to stop him from scamming people?'' she demanded to know. Despite Monte's claims about having nothing to do with Parker Taylor, when she rang the detective agency the previous day, who should answer the phone? Frank Monte.