The man arrested for allegedly throwing hundred-dollar notes from a building in busy Kowloon is said to have had problems with the law in the past.
Mr Wong Ching Kit, 24, is a former swimming instructor who was sentenced to 160 hours of community service for stealing a mobile phone at a public swimming pool in 2012, local media HK01 reported.
It also said there were some online forums that suggested that Mr Wong, whose original name is Guan Zi Jie, could have been involved in a case in which a man known only as Mr Mu disappeared with funds meant for a purported swimming meet.
But he did not address those accusations online, it added.
Mr Wong later started dealing in cryptocurrencies, and called himself "Coin Young Master".
He created a Facebook page to promote cryptocurrencies on Jan 1 this year and had been aggressively pushing Filecoin recently, HK01 said. Some media identified the Facebook page as Epoch Cryptocurrency.
In June, he took over all the shares of Coin's Group from a man known only as Mr Lau.
The latter is a director of five firms that have dealings in areas such as charity, finance and entertainment. They are said to be subsidiaries of a holding company that was one of the firms supposedly implicated in a London gold trading scam this year, HK01 reported.
The scam involved the employment of young, pretty women to flaunt luxury items like watches and cars on social media to lure victims into investing in gold, with promises of high returns.
The report added that there was a change in the holding firm's management earlier this year and Mr Lau resigned from the board.
In Mr Wong's Facebook posts on Epoch Cryptocurrency in July, he started flaunting his Lamborghini and landed property in Sai Kung.
The Facebook page had a live video last Saturday that showed a man clad in a black hoodie saying in Cantonese: "I hope everyone here will pay attention to this important event... (I) don't know whether any of you will believe money can fall from the sky."
Subsequent video footage, which went viral, showed wads of HK$100 (S$18) notes raining down from a building in Sham Shui Po while a frenzied crowd tried to grab them.
Mr Wong was arrested on Sunday afternoon for behaving in a disorderly manner in a public place and was still under detention last night, said Apple Daily. It added that he was in handcuffs and accompanied by the police as they made their way to his office in Tsuen Wan last night.
Mr Wong had planned to hand out meal coupons outside a restaurant in Sham Shui Po at 4pm on Sunday but was arrested before he could do so.
More arrests could happen, as local reports said that the police believed Mr Wong was not the only one behind the money stunt.