This statement was made in response to a query. As such, it is not fully researched, but links to more information are provided. Please contact me about any examples of political surveillance not mentioned below.
There appear to be several types of politically motivated surveillance in Hong Kong. Some types appear to be carried out by the Hong Kong government and police, others by mainland agents.
The Hong Kong Immigration Department apparently has a blacklist of people not allowed into Hong Kong, such as, most recently, Brendan Rogers of the United Kingdom, Kenichiro Wada of Japan, and Taiwanese activists, all of whom have in common pro-democracy allies in Hong Kong. When asked by reporters, the department either avoids responding or refuses to acknowledge that it keeps such a list and refuses to discuss individual cases. Statements made by government officials suggest Hong Kong has been pressured by the Communist Party to deny entry in some cases.
The Hong Kong police routinely video demonstrators, though they have been repeatedly criticized by the United Nations and human rights groups such as Human Rights Watch for doing so. The public doesn’t know what happens to the hundreds of hours of video footage as the police refuse to make available to the public whatever guidelines on use of video footage there may be.
When it was revealed in July that the Hong Kong government is considering banning the Hong Kong National Party under the Societies Ordinance, HKNP was presented with a dossier of material that showed the police had been monitoring it going back two years, even though no one in HKNP has ever been arrested, let alone formally charged with a crime. Are there other political groups in Hong Kong that the police are “investigating”? What procedures does the police follow to ensure that its investigations do not infringe civil liberties? What is the dividing line between legitimate criminal investigation and political surveillance?
Both the Immigration Department and the Police Force are black boxes on these matters, and it is understandable that the cases that have come to light lead many pro-democracy politicians and activists to suspect those cases are but the tip of the iceberg.
The bookseller Lee Bo and the tycoon Xiao Jianhua were abducted from Hong Kong and transported to the mainland where they ended up in state custody. Surely they must have been under surveillance in the lead-up to the abductions. The rumor on the street is that Lee Bo was kidnapped by a triad operating out of a bathhouse in Jordan (the Hong Kong neighborhood, not the country), presumably working on behalf of a mainland intelligence agency. Hong Kong police never gave any sign that they investigated such rumors. Even though it was suspected that Lee Bo had left Hong Kong without going through any immigration controls, a crime, the Hong Kong police decided not to press criminal charges against him or pursue the investigation further. The bookseller Lam Wing-kee reported being under surveillance upon returning from his detention on the mainland.
The pro-democracy politician Eddie Chu reported having received death threats and having been followed. The Democratic Party member James To reported having been under surveillance most likely by mainland agents in 2015. Joshua Wong reported being followed in Taiwan, and Chan Kin-man reported being monitored in Hong Kong. Retired Hong Kong police officers say mainland intelligence services have recruited former Hong Kong police officers to conduct political surveillance. The League of Social Democrats member Tsang Kin-shing reported being followed during Xi Jinping’s visit to Hong Kong in 2017. Both Andy Chan and Edward Leung reported being followed by reporters from the Communist Party’s Wen Wei Po, raising the question of to what extent Communist Party newspapers also conduct surveillance. Baggio Leung has reported being routinely followed by police officers and “people who dress like secret agents in a comedy film” whenever he shows up at protests.
Most recently, the political groups Demosistō and Studentlocalism have reported incidents having to do with surveillance. Two low-profile Demosistō members were detained by police on the mainland. There is no way the mainland authorities could have known of them unless they were conducting surveillance of some sort. Studentlocalism said family members of two of its members were contacted while on the mainland about their activities. Again, it would have been impossible to ascertain their identities without some kind of surveillance. None of the four activists in these cases were public figures.
In many of these cases, those monitored have complained that the Hong Kong police has done an insufficient job of following up on their reports of being under surveillance. All of these cases suggest a pattern of political surveillance by both Hong Kong authorities and mainland agents. Many in the pro-democracy movement simply assume they are under surveillance and act accordingly. When Andy Chan was asked if he reported the suspected surveillance to the police, he responded, No, it would be useless. That lack of confidence in the Hong Kong police to investigate such matters is widely shared. That is understandable given that, in some cases, the police appear to be the ones conducting the surveillance.
To summarize, there is evidence that the following governmental agencies monitor Hong Kong citizens and foreigners based on their political beliefs: 1) Hong Kong Police Force, 2) Hong Kong Immigration Department, 3) mainland Ministry of Public Security, 4) mainland Ministry of State Security, 5) mainland police, 6) Communist Party-owned newspapers based in Hong Kong. In addition, there are signs that other shadowy groups, including intelligence agencies and triads, monitor Hong Kong citizens based on their political beliefs.