Six senior employees of Hong Kong’s closed pro-democracy tabloid Apple Daily pleaded guilty to collaborating with foreign forces on Tuesday and could face life imprisonment.

Their convictions were part of a landmark case in which the city’s sweeping national security law, imposed by Beijing in 2020 to stifle dissent, was used for the first time against a news organization and its staff.

For years, Apple Daily has harshly criticized the Chinese government and backed the pro-democracy protests that rocked Hong Kong in 2019.

It collapsed last year after its funds were frozen and many of its officers – including founder Jimmy Lai – were charged with national security violations.

Four former senior editors and two ex-executives pleaded guilty to “conspiracy to collude with foreign forces to endanger national security” in Hong Kong’s Supreme Court on Tuesday.

Former employees included Board Chairman Cheung Kim-hung, Associate Editor Chan Pui-man, Editor-in-Chief Law Wai-kwong, Editor-in-Chief Lam Man-chung, and Senior Authors Fung Wai-kong and Yeung Ching-kee.

Prosecutors accused them of using Apple Daily to distribute content calling for foreign sanctions against China, providing more than 160 articles published since April 2019 as evidence.

The national security law, which criminalized foreign collusion, only came into effect on June 30, 2020.

Prosecutors dropped the incitement charges in exchange for the defendants pleading guilty to collusion, which carries a maximum sentence of life in prison.

The six have been in pre-trial detention for nearly a year and a half and will only be convicted once the trial of Lai and three Apple Daily companies is complete.

A senior prosecutor told the court that some of the six would testify at the trial.

Lai and the companies have pleaded not guilty. Her trial is scheduled to begin in December.

Hong Kong fell steadily in the press freedom rankings after its handover to China in 1997, but that decline accelerated dramatically after Beijing launched its crackdown on dissidents following the 2019 protests.