According to an insider, Chinese police raided the Shanghai office of WPP's media investment group GroupM and detained an advertising executive. WPP is headquartered in London.
The person stated that the police interviewed other local executives during the raid, including Patrick Xu, the CEO of Groupon China.
Xu Jun could not be immediately reached for comment. The Shanghai police did not respond to the reporter's request for comment.
Media outlets including the Financial Times earlier reported on the raid and detention incident.
China has adopted an increasingly tough attitude towards foreign companies, despite calls from the Chinese leadership to increase foreign investment to support a slowing economy.
Chinese authorities raided the representative office of due diligence company Mintz Group this year, questioned employees of American consulting firm Bain&Co., and implemented strict new data regulations. The police also raided the office of expert network consulting company Capvision, which has close cooperation with foreign consulting companies in China.
Chinese authorities have banned some executives working for foreign companies from leaving Chinese Mainland. The Japanese government announced last week that China has officially arrested a senior executive of the Japanese pharmaceutical company Astellas Pharma Inc., who has been detained since March.
  In July of this year, China began implementing a new version of its anti espionage law, giving the country greater control over a series of digital activities.
These actions have dampened the confidence of American companies in China, and the related confidence index has dropped to its lowest point in decades. Although many foreign companies continue to conduct business activities in China, executives have also expressed increasing concerns about China's opaque legal and business environment.
It is currently unknown why Qunyi was subjected to surprise inspections or why executives were detained, as well as whether the investigation is related to China's national security issues.
Groupon's parent company WPP is the world's largest advertising holding company, with advertising companies including Ogilvy, Wunderman Thompson, and VMLY& R. According to WPP's 2022 annual report, China is WPP's fourth largest market. WPP recently announced the merger of VMLY& R and Wunderman Thompson.