Hong Kong media tycoon and pro-democracy advocate Jimmy Lai is heading back to detention after the city’s highest court revoked his bail Thursday.

The 73-year-old Lai was arrested Dec. 3 and spent three weeks behind bars before posting a $1.2 million bond just last week. Prosecutors appealed the decision to grant Lai bail, claiming the judgment was erroneous.

Lai was barred from using Twitter, granting interviews or colluding with foreign forces.

The owner of Next Digital media company was initially charged with fraud, with prosecutors accusing him of violating terms of the company’s lease of its office space. Lai has since been charged under Hong Kong’s new national security law for “foreign collusion.”

Lai was first arrested under the new law on suspicion of foreign collusion in August. Hours after his arrest, more than 100 police officers raided the headquarters of Next Digital, which publishes the newspaper Apple Day. The newspaper livestreamed the raid on its website, showing officers roaming the newsroom as they rummaged through reporters’ files, while Lai was led through the newsroom in handcuffs.

Lai was eventually released on bail after 40 hours in custody.

Lai is already in legal jeopardy for his pro-democracy activism. He was one of 15 activists arrested earlier this year and hit with seven charges, including organizing and participating in unauthorized assemblies and inciting others to take part in an unauthorized assembly.

He is one of the highest-profile Hong Kongers targeted by the new security law since it went into effect in July. Under the law, anyone in Hong Kong believed to be carrying out terrorism, separatism, subversion of state power or collusion with foreign forces could be tried and face life in prison if convicted.

The new law was imposed by Beijing in response to the massive and often violent pro-democracy demonstrations that engulfed the financial hub in the last half of last year, and is the cornerstone of its increasing grip on the city, which was granted an unusual amount of freedoms when Britain handed over control in 1997.