BEIJING — China has released five staff members of US due diligence firm Mintz Group, two years after they were detained as part of a crackdown on consulting firms working with foreign businesses.

Their detention in March 2023 came at a time of heightened suspicion of foreign espionage in China and kicked off a wave of raids on consultancy firms such as Bain & Company and Capvision Partners.

"We are grateful to the Chinese authorities that our former colleagues can now be home with their families," Mintz Group said in a statement.

Their release comes at the conclusion of a business forum in Beijing attended by dozens of top foreign executives, including Apple's Tim Cook and Pfizer's Albert Bourla.

China has been trying to revive foreign investment in its sluggish economy. Government data released in February showed that foreign direct investments plunged 99% in the last three years.

At the forum on Sunday, Vice Premier He Lifeng reassured business leaders of the country's "unswerving" commitment in "welcoming multinational corporations and sharing development opportunities [with them]".

Mintz Group noted that all five employees who were released are Chinese nationals.

They were detained by China's public security bureau after a raid of the company's Beijing office in March 2023.

Mintz Group said at that time that it did not receive any official legal notice about the raid.

Chinese authorities have not commented on the detentions and the subsequent release.

Later in 2023, Mintz Group was fined $1.5 million for doing "unapproved statistical work". By the time, the company had closed all its offices in mainland China and Hong Kong.

Reuters news agency had reported on the company's involvement in examining the possible use of forced labor in supply chains linked to China's Xinjiang region. — BBC