New Delhi, Dec. 15 -- Jimmy Lai, the pro-democracy former Hong Kong media mogul and outspoken critic of Beijing, was convicted in a landmark national security trial in the city's court on Monday, which could send him to prison for the rest of his life.

Three government-vetted judges found Lai, 78, guilty of conspiring with others to collude with foreign forces to endanger national security and conspiracy to publish seditious articles. He pleaded not guilty to all charges.

Lai was arrested in August 2020 under a Beijing-imposed national security law that was implemented following massive anti-government protests in 2019. During his five years in custody, much of it in solitary confinement, Lai has been convicted of several lesser offense...