The affected investors, aged 20 to 49, suffered losses of between HK$20,000 and HK$1 million each, the party said. Some had made reports to police earlier.

Wong, known online as “Coin Young Master”, was widely thought to be behind a stunt in Sham Shui Po last month in which at least HK$6,000 in cash was thrown from a high-rise. He has denied any involvement but moments before stacks of banknotes fluttered off the building, Wong was seen stepping out a flashy car and asked onlookers in a video he posted online if they “believe money will fall from the sky”.

Wong runs a Facebook page and various online groups to promote cryptocurrencies, including “File Cash Coin”, which he said he co-founded.

Suspect in Sham Shui Po stunt donates HK$92,000 to feed poor

After the Sham Shui Po incident, he was arrested on suspicion of disorderly conduct in public but released on bail. As of Sunday, he faced no charges.

On Sunday, the investors claimed Wong had misled them into buying “mining equipment” for the digital currency “filecoin”. They got to know Wong’s cryptocurrency business through social media and claimed they were told their investment could turn a profit within three months.

But it turned out the cryptocurrency was not yet tradeable on the market. Promises of refunds were never honoured, they said.

One affected investor, who gave her name as Ms Chiu, said she invested more than HK$120,000.

“At first, I was told I could get a refund if filecoin could not be launched in time,” she said. “But when we asked for a refund, he used delaying tactics and made different excuses to turn us down.”

Democrat Ramon Yuen Hoi-man, a Sham Shui Po district councillor helping the investors, urged the government to step up measures to regulate cryptocurrencies.

He later said he received a threatening phone call and reported it to police. But he added that the caller did not mention anything related to Wong.

Wong later hit back at critics in a post uploaded on his Facebook page. He did not comment on the investors’ allegations directly but said he had been unfairly targeted.

“I sell mining machines only but am treated as if I have killed people. When they make money, there is no thank you. When they lose money, they call it a scam,” he said.

“When they make money, they won’t share their profits with me. But when they lose money, they ask me for money back.”

Last month, Wong dismissed allegations against his cryptocurrency business as part of a smear campaign launched by business competitors.

“Can you define cheating? They say I cheated them. If they made money, would they still say they were cheated? You either make money or lose money in doing business,” he said.

“If a person thinks he has fallen victim to fraud, he should report it to police.”

A police spokesman on Sunday said nine men and a woman, aged 29 to 41, had previously made reports claiming they had been cheated of a total HK$940,000 over investments in Wong’s cryptocurrency business.

More than US$195.3 million defrauded from firms in first 10 months of 2018

A police source earlier said the force would launch an all-round investigation into Wong and also probe whether he was involved in money laundering, as it was reported there was an eight-digit sum in his bank accounts.

“The 24-year-old has to explain how he ended up with that large sum of money. It could be considered money laundering if one fails to explain the source of income,” the insider said.

Wong was born Kwan Tsz-kit and previously worked as a swimming instructor. He was convicted of theft and sentenced to 160 hours of community service in 2012 and changed his name afterwards.

Additional reporting by Alvin Lum