BEIJING, China (Reuters) – On Monday, China sentenced a 78-year-old US citizen to life in prison on spying charges, highlighting the deterioration of ties between Beijing and Washington in recent years.

The claims against John Shing-Wan Leung, a Hong Kong permanent resident, have not been made public.

According to a news release posted on the Suzhou city’s intermediate court’s social media website, Leung was detained by the regional office of China’s counterintelligence agency on April 15, 2021. When he was imprisoned, China had already closed its borders, increased domestic travel restrictions, and instituted social controls to combat the spread of COVID-19.

Such investigations and prosecutions are conducted in private, with little information made public other than broad claims of infiltration, intelligence gathering, and jeopardising state security.