The National Security Department has accused and arrested dissenting voices in Hong Kong for "endangering" the national security, including pro-democracy politicians and protestors. Some websites were also reportedly banned by the department, including
Hong Kong Watch. Police in the department had to be vetted to review the allegiance and loyalty to China, non-disclosure agreements are signed also. Senior police of the department has been sanctioned by the United States, including Edwina Lau, Frederic Choi, for their role in enforcing the NSL. According to
Ming Pao, police from the NSD regularly, sometimes monthly, met the activists to learn of their latest activities. One claimed he was contacted four times by the security police within one month, warning them any movement on "special days" could lead to arrest. These meetings increased significantly in 2023, as members of NGOs and former local councillors were approached for the first time. In December 2022, in the case against
Stand News, it was revealed that officers from the National Security Department had archived 587 articles from the website, sought prosecutors' advice on 30 of them, and then discarded the remaining articles. The defense argued that a fair trial would be impossible, since evidence was destroyed. In May 2023, the department confiscated from storage the
Pillar of Shame commemorating victims of the
Tiananmen Square crackdown. It cited an ongoing case under investigation. The sculpture was on exhibit at the
University of Hong Kong before campus authorities removed it in 2021 and placed it in storage at the university's Kadoorie Centre. == Impersonation incident ==