Police enforcing Hong Kong’s national security law have a watch list of residents under investigation for allegedly violating the Beijing-imposed legislation to be intercepted and arrested if they attempt to flee the city, sources have told the Post . The list includes more than 50 people released on bail after being arrested under the national security law, most of them having surrendered their travel documents as surety. “Those on the list will be intercepted by law enforcers if they try to leave Hong Kong through a legal immigration channel such as the airport or a border checkpoint,” one security source said. The source remained tight-lipped on who and how many people were on the list. A law enforcement insider speaking on condition of anonymity said police could also ask for anyone suspected of a criminal offence, including national security violations, to be added to a separate watch list managed by the Immigration Department to prevent their escape from the city. The offence in question would have to fall under an official category of serious crimes and the request to add the suspect on the immigration watch list would have to be approved by a senior police officer, the source added. The existence of the national security watch list was confirmed after a senior editorial writer at the now defunct, tabloid-style Apple Daily , Fung Wai-kong, was arrested over the weekend while attempting to leave the city. The source said he was on the police list. Fung, 57, was intercepted at Hong Kong International Airport at around 10pm on Sunday as he was catching a flight bound for Britain. The Post reported last December that national security police were looking for about 30 people overseas wanted on suspicion of violating the city’s law banning acts of subversion, secession, terrorism and collusion with foreign forces. Apple Daily editorial writer arrested at airport while trying to leave Hong Kong They included overseas-based activists as well as others who left the city before and after the enactment of the law on June 30 last year. Among them were fugitive former opposition lawmakers Nathan Law Kwun-chung, Ted Hui Chi-fung and Sixtus Baggio Leung Chung-hang, along with former British consulate employee Simon Cheng Man-kit and activist Ray Wong Toi-yeung. Others included independence advocate Wayne Chan Ka-kui, former member Lau Hong of the now-disbanded separatist group Studentlocalism, who changed his name to Honcques Laus, and US-based Samuel Chu of the Hong Kong Democracy Council. Most of the fugitives are now in Europe, the United States and Taiwan, and face arrest if they return to the city. Police arrested Fung of Apple Daily on suspicion of collusion with foreign forces to endanger national security, an offence that carries a maximum penalty of life imprisonment. Fung was accused of writing several articles calling for foreign sanctions after the enactment of the sweeping law, another source said. Police escorted Fung to his home in Sha Tin for a search before taking him to the headquarters of the national security department in Wan Chai. As of Monday night, he was still being held for questioning and had not been charged. Is Hong Kong’s national security law being weaponised? Fung had been an editorial writer for Apple Daily since 1997. He was also managing editor of the paper’s English news service before it was scrapped last week, and a columnist for local news portal CitizenNews. Fung was the second editorial writer for Apple Daily to be arrested over the same offence in four days, after Yeung Ching-kee. Yeung, 55, was detained last Wednesday and later released on bail pending further investigation. A police spokesman on Monday said investigations were ongoing and further arrests were possible. Fung and Yeung were arrested over articles calling for foreign sanctions, following the detention of five top Apple Daily executives on June 17. Police also froze HK$18 million (US$2.3 million) of the paper’s assets. Two of the executives – editor-in-chief Ryan Law Wai-kwong and publisher Cheung Kim-hung – were charged with conspiring to collude with foreign forces. Apple Daily has been accused of publishing more than 30 articles calling for foreign sanctions against Hong Kong and mainland China. The 26-year-old newspaper, founded by media tycoon Jimmy Lai Chee-ying , who is currently serving time behind bars for taking part in unlawful assemblies related to the 2019 anti-government protests , shut down last week saying it had run out of funds to continue. National security: what is Article 23 and why is it back in the spotlight? Police have arrested 117 suspects – 95 men and 22 women, aged from 15 to 79 – and charged 61 of them until now under the national security law. The first person to be charged under the law was Tong Ying-kit, 24, who was arrested in Wan Chai on July 1 last year after he allegedly rode his motorcycle into a group of police officers. Tong, who had a black flag sticking out of his backpack bearing the slogan, “Liberate Hong Kong; revolution of our times”, was charged with incitement to commit secession as well as terrorism.