Hong Kong (CNN)Hong Kong's national security police are investigating the group behind the city's annual June 4 vigil, which commemorates pro-democracy protesters who died in the 1989 Tiananmen Square crackdown in Beijing, according to a letter to organizers seen by CNN.
Hong Kong national security police investigate Tiananmen Square vigil organizers
The Hong Kong Alliance in Support of Patriotic Democratic Movements of China must submit personal details of all its directors and members, including their names, dates of birth, addresses, contact information and roles, the police letter said. It also demanded the group -- formed more than three decades ago to support those protesting for democracy in Beijing -- provide all meeting records with political groups in Hong Kong, Taiwan and overseas, as well as its source of income.
The police letter said the request was made because it was "reasonable to believe" it would help investigate possible crimes against national security. The alliance must provide the information within 14 days, or they could be prosecuted, it added.
Hong Kong police confirmed to CNN in a statement that they had requested "certain persons" provide information that is "related to the maintenance of national security," but declined to provide more details.
The letter came after public broadcaster RTHK reported this week that the alliance has considered disbanding following Beijing's promulgation last year of a sweeping national security law that criminalizes secession, subversion, terrorism and collusion with foreign forces.
In the wake of the legislation, the city's political and social landscape has been transformed. Under the security law, protesters, journalists and pro-democracy figures have been arrested; newsrooms have been raided and forced to shut down; textbooks, films and websites face new censorship; and civic organizations including labor unions have folded after pressure from authorities.
The Hong Kong Alliance has held the annual candlelight vigil on the anniversary of the crackdown since 1990.
The events of Tiananmen Square began with protesters in Beijing, mostly college students, gathering in the heart of the Chinese capital to mourn the death of an ousted former leader -- then, to push for governmental reform and greater democracy. In the early hours of June 4, the Chinese military entered the square, with orders to put down the protests.
No official death toll has ever been released, but rights groups estimate hundreds, if not thousands were killed. The protests and crackdown have been wiped from the history books in China, censored and controlled. The annual candlelight vigil in Hong Kong has been, for decades, the only mass memorial held on Chinese soil.
But the vigil's days appear to be numbered. This year's event was banned by authorities, citing coronavirus restrictions. Hong Kong's Security Bureau also warned that attending or promoting any June 4 rally could violate the national security law and result in imprisonment.