Angry investors demanding the return of hundreds of millions of dollars they pumped into one of Macau's biggest casino junket operators staged fresh protests yesterday amid growing fears that the city's spectacular rise to global gaming dominance could be in danger of unravelling. Already reeling from the combined effects of Beijing's anti-corruption drive and the mainland's economic slowdown, junket operators who bring in the big-spenders that account for the vast bulk of casino revenues face a backlash from disgruntled investors - some from Hong Kong - who fear the former Portuguese enclave's gaming dream is turning into a nightmare. Over the past week investors in Dore Holdings - which operates VIP rooms in Wynn Macau - have staged a series of public protests calling for the return of millions of dollars they invested in the company after it emerged that between HK$200 million and HK$2 billion had been "stolen" by a rogue former employee . READ MORE: Wynn shares sink after reports HK$2 billion was stolen from junket group operating out of Macau casino Macau police have confirmed they are investigating 38 Dore investor complaints - five from Hong Kong people - involving HK$390 million. But documents seen by the Sunday Morning Post suggest disgruntled investors are seeking almost double that amount, HK$670 million. Casino insiders fear the Dore theft - of which the junket operator insists it is victim - is symptomatic of a wider problem that could spell the beginning end for the often shady businesses at the heart of Macau's gaming success. "The number of VIP rooms is shrinking and revenues are dropping like a stone, something has to give because without the huge cash-flows they have become used to, the junket operators will not be able to meet their commitments to the casinos and somebody is going to have to pay," said a veteran casino insider. Fears were further stoked when on Friday night one of city's biggest junket operators - not Dore Holdings - warned on social media that unless something was done to arrest the decline, "Macau's gambling business will enter a destructive black hole". He likened his business and others to banks and described them as an "international clearing house for funds going overseas". Read more: Macau casinos take out insurance policies after rise in hostage-taking over gambling debts The comments have raised concerns the junkets' part in giving Macau casinos a reputation as a money laundering centre for massive illegal cash flows out of the mainland will now come under the scrutiny of not only Beijing but international anti-money laundering regulators. "To describe Macau junket rooms as a clearing house for funds going to and from other jurisdictions is going to hugely embarrass the Macau government and will likely invite scrutiny from global watchdogs," the insider said. In April 2014, in a little-publicised case, an agent from another VIP room operator, named Kimren, fled with between HK$8 billion and HK$10 billion. Macau lawmaker Jose Pereira Coutinho said he received 53 complaints about the Dore case. "The background of the investors is diverse. Some of them are housewives, others are engineers, architects, others work in casinos," he said. "Some signed a contract with a certain VIP room, others made bank transfers and only have the proof of the transfer, others paid in cash and received a receipt from a VIP room." Read more: Macau's casino slump is an opportunity to retool the economy Verbal agreements are legal in Macau. However, proving them in court can be hard to do. The Post learnt junket operators used several investment schemes. "Many people - even officials - have invested their money in junket operators in order to receive interest after a year, about 2 per cent a month," said a source familiar with the gaming industry, giving an example of a common scheme. The same source noted that the "industry went through a golden period, which many people thought would be endless. And many people were greedy, of course, there was so much money to be made." Macau has seen sharp rises in lawsuits filed by junket operators chasing bad debts and in illegal detentions of casino debtors. Coutinho urged the government to intervene and said the operator had to assume some of the responsibility. "People trusted this junket operator because it operates under Wynn, which is supervised by the government," he said. The Dore Group said that the company's rogue employee, whose whereabouts remain unknown, sought funds from the group's clients and other people by unlawfully using the junket's name. The group, which described itself as a victim, said the suspect forged seals and lured investors with extremely high interest rates. The group stressed such conduct was "against the law". The Gaming Inspection and Coordination Bureau said on Friday only authorised credit institutions could receive deposits and other reimbursable funds. Michael Weaver, Wynn's senior vice-president of marketing, said Dore was operating as normal in Wynn Macau. "Because Dore is an independent and licensed company, any direct financial relationships it has with parties outside of the resort are the concern and responsibility of Dore," he said. Gross gaming revenue in Macau fell 35.5 per cent in August year-on-year. The opaque world of Macau's junket operators Junket operators - also known as gaming or VIP room promoters - have been the bedrock of the Macau gaming industry for decades and for just as long have struggled with a reputation for being behind massive flows of illicit funds out of the mainland. They arrange hotel rooms and other perks, but their main role is to provide credit and help clients skirt mainland currency controls. However, the system that regulates them is at best opaque Although ostensibly licensed by the Macau Gaming Inspection and Coordination Bureau, shady investors who hide behind a myriad of company and family connections often hold the real power. They are also the ones responsible for collecting debts, often using illegal means. In the first six months of this year, 170 people were held against their will mostly inside casinos, official figures showed. "It is clear that Macau casino junkets are a front for organised crime groups. They have made billions moving money illegally out of China and engaged in money laundering as a service. They cannot expect to be treated as normal companies," said Martin Purbrick, the director of security and integrity at the Hong Kong Jockey Club and also a former Hong Kong police officer. "Governments need to … ensure they do not gain footholds in business in other sectors."