This undated photo shows the building of West Kowloon Magistrates' Courts in Cheung Sha Wan, Hong Kong.(CALVIN NG / CHINA DAILY)

Four higher-ups of now-closed tabloid Apple Daily on Thursday were denied bail by West Kowloon Magistrates' Courts for colluding with foreign countries or with external forces to endanger national security.

The four charged are the tabloid's former executive editor-in-chief Lam Man-chung, former associate publisher Chan Pui-man, ex-editorial writers Fung Wai-kong and Yeung Ching-kee. They appeared in the court in the morning.

The case was adjourned to September 30 for further investigation by the prosecution

On Wednesday, the police's National Security Department arrested and detained Lam, while also revoking the bail of the remaining three after they were released last month.

READ MORE: HK police arrest another Apple Daily editor under security law

Since June, a total of eight people who held important positions in Apple Daily and its parent company Next Digital have been arrested in different police operations on similar charges, with the tabloid's founder Jimmy Lai Chee-ying remains in jail for his roles in several unlawful assemblies.

Judge So Wai-tak, chief magistrate of the West Kowloon Magistrates' Courts who adjudicated the case, rejected all defendants' applications for bail.

The case was adjourned to Sept 30 for further investigation by the prosecution.

READ MORE: HK political, legal experts back Apple Daily arrests