Grant told the Herald they had received no response from the company's director and shareholder Tiavare Richard Curtis Joseph, a process complicated by the level 3 lockdown in Auckland preventing Waterstone staff travelling to Porirua to visit in person.
Grant said while more work was needed to trace payments through bank accounts, it appeared the firm had dozens of investors with "losses in the low millions".
He anticipated referring the matter to the Serious Fraud Office once he had a clearer picture of what had happened. "We'll give the SFO a bit of background ... in a month."
Investors spoken to by the Herald said the scheme was run with a striking lack of paperwork and in recent months Joseph had promised to repay all investors.
One investor was promised their $82,868 investment would attract 16 per cent returns as a "secured high risk return investment".
Joseph did not respond to Herald calls, emails or social media messages.
Joseph also directs and operates construction company Kainga Ora and appears to have been more commonly known in the community as Richard or Ritchie Wineera.
In 2017 he secured a board role on high-profile local charity the Porirua Whanau Centre, with his appointment praised by fellow board members as adding financial and construction expertise.