In March 2023, Mintz Group said Chinese authorities had detained five Chinese staff members from its office in Beijing and forced the firm to cease its operations there.

Beijing's foreign ministry later said the company was under investigation for suspected "illegal operations", but did not provide details.

"We understand that the Mintz Group Beijing employees who were detained, all Chinese nationals, have now all been released," a Mintz spokesperson told AFP in a statement on Tuesday.

"We are grateful to the Chinese authorities that our former colleagues can now be home with their families."

Headquartered in New York, Mintz specialises in conducting investigations into fraud, corruption and workplace misconduct allegations, as well as background checks.

The company employs over 280 investigators in 12 offices worldwide, according to its website.

China targeted other US firms during its 2023 crackdown on the sector, including consultancies Bain & Company and Capvision.

Analysts warned at the time that the raids indicated that Beijing was increasingly prioritising national security concerns over attracting international business.