Four men and a woman were arrested on Monday for their alleged involvement in a terrorist plot to bomb the city’s courts and transportation networks, bringing to 14 the number of suspects arrested in the case.

The five new suspects, aged 15 to 37, were arrested by the Hong Kong Police Force’s National Security Department on suspicion of conspiring to commit terrorist activities — a violation of Article 24 of the National Security Law for Hong Kong.

All 14 suspects who have been arrested since July 5 in the case belong to a local radical separatist group, police said

Police did not release their identities. According to local media, three of the arrestees are students who were allegedly supposed to plant the bombs, while the two adults served as patrons.

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In response to a media inquiry by China Daily, police said they found “items” related to the alleged bombing plot at the latest arrestees’ residences and workplaces, but did not elaborate.

All arrestees have been detained for investigation. Police said they are not ruling out further arrests.

All 14 suspects who have been arrested since July 5 in the case belong to a local radical separatist group, police said.

Of the six secondary school students arrested last week, three have been charged with conspiracy to commit terrorism, and they were denied bail after appearing at the West Kowloon Magistrates’ Courts on Wednesday. Police said the three were aided and recruited online and through street booths.

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During the police raids conducted last week, investigators seized the highly explosive chemical TATP — triacetone triperoxide — in a hostel room that had allegedly been turned into a bomb-making laboratory, in the busy business district of Tsim Sha Tsui. About HK$600,000 (US$77,250) linked to the group was also traced and frozen. When announcing the arrests last week, police said the plot was well-organized and was planned to be carried out before mid-July.