The US District Court in the Northern Marianas has unsealed an indictment against three people who allegedly conspired to hire unauthorised foreign workers.
They worked on the construction of the Imperial Pacific casino on Saipan.
The trio face numerous charges including the unlawful employment of foreigners and money laundering.
Their scheme allegedly lasted until at least March 2017, and resulted in an influx of more than 600 illegal workers, many of whom were inexperienced or unqualified.
On the money laundering charges, the defendants allegedly made money transfers totalling over 24 million US dollars.
Meanwhile Imperial Pacific has been reminded it still needs to pay its 15 million dollar casino license fee by next Wednesday.
In the past the company was penalised $US25,000 a day for late payment.