“The investigation is still ongoing, and VNG continues to actively cooperate with the authorities, ensuring compliance with their requests,” VNG said in a statement, adding its business would be operating normally.

The statement did not provide a reason for the investigation.

Calls to police seeking comment were not answered.

A person familiar with the matter said the investigation would include VNG and two related companies, Zion JSC and Thanh Son Communication Co.

On Saturday, VNG said in a statement it had appointed Kelly Wong as acting general manager. It did not specify whether Wong was replacing Le Hong Minh, the company’s founder and general manager, in the new role.

VNG, with 14 offices across the world, had planned to go public in the US, but in January withdrew its initial public offering registration there without explaining why.

Founded in 2004, VNG was Vietnam’s first “unicorn” – a startup valued at $1 billion or more. Its businesses include online games, payments, cloud services and Vietnam’s most popular messaging app, Zalo.

Its revenue in the first half of this year rose 30.3% from a year earlier to 4.3 trillion dong (US$170 million), its financial statement showed, while its net loss shrank 51% to 585.8 billion dong.