All three Studentlocalism members were previously arrested in July
in connection with posts made on social media by a page claiming to represent the international arm of the group.
The Hong Kong branch of the organization said it had disbanded soon after the national security law was imposed on the city by Chinese authorities, banning secession, subversion and collusion with foreign forces.
Police accused Chung and others still based in Hong Kong of continuing to advocate for the city's independence from China, a crime that carries with it a sentence of three to 10 years, or up to life imprisonment for offenses of a "grave nature." The accused denied having any connection to the allegedly secessionist posts in question.