A large number of national security police raided the office of the students' union of University of Hong Kong around 3pm on Friday.
The office of the students' union was closed at first, the university then opened the office and let the police in.
A spokesperson of the university confirmed that the police have entered the campus to investigate a case with a Court Order, and said the school is obliged to act in compliance.
The raid was triggered by a suspected violation of article 27 of the national security law, according to sources.
It was understood that police searched the conference room of the union's council, the office of Undergrad, a publication by the union, as well as the office of Campus TV.
Earlier the students' union passed a motion in paying tribute to the attacker in Causeway Bay. Although the council soon retracted the motion and apologized, the act still drew fire from the university and different government sectors.
Government officials, including leader Carrie Lam Cheng Yuet-ngor, warned their act would be in violation of the national security law. She also supported an investigation to be conducted either by the police or by the school management.
The university on Tuesday disowned the students' union, saying it will no longer recognize its role at the university as an independent society.
The school also sent an ultimatum to the union the next day, requesting them to move out of their office located at the Composite Building within a week.
