Based on CCTV footage and video seized during a raid of the student union offices, police concluded the four had spoken during the meeting, with some praising the assailant’s behaviour and describing him as “a martyr” and “courageous”, according to Senior Superintendent Steve Li Kwai-wah of the force’s National Security Department.

Police also confirmed that all students present had paid a silent tribute to the attacker at the start of the meeting before discussing the motion, which Li said was aimed at “praising the assailant and recording him in the history of the student union”.

According to Li, the students’ “political speeches”, live-streaming of the meeting and sharing of the vote results on social media constituted the crime of “advocating terrorism” under the national security law.

“The motion was staggering, as it beautified and glorified terrorism as well as the indiscriminate attack. It also encouraged people to commit suicide,” he told a press briefing.

“They were so eager to present these messages to the public through their propaganda.”

Li said that apart from those who had spoken at the meeting, the force would also interview the others in attendance to ask why they had voted as they did. Thirty of the 32 council members present at the meeting voted in favour of the motion, while two abstained.

Police would consider follow-up actions based on their answers, Li added, possibly arresting them, confiscating their passports or searching their homes.

“Our investigation will continue, and we hope to clarify their roles as soon as possible, so that students can return to their normal learning lives soon,” Li said.

Asked whether the council’s subsequent withdrawal of the motion after HKU condemned its conduct should have factored in how the case was pursued, Li said the force was required to act according to the law.

“As a law enforcement officer, I do not have many choices. It would be seen as dereliction of duty if I saw someone violating the law and did nothing,” he said. “But we will, of course, mention to the court how the students handled the matter, including the withdrawal of the motion.”

Charges were not likely to be pursued against those who had rebroadcast the live stream, as they might not have been aware of the context, Li said.

HKU cuts student union ties after Carrie Lam slams motion backing police assailant

He declined to answer when asked whether police also planned to investigate pro-establishment activists who had publicly sympathised with defendants jailed last month over the Yuen Long MTR station attacks on July 21, 2019, in which about 100 stick-wielding men attacked protesters and commuters.

In an internal email sent to all law students, HKU law dean Professor Fu Hualing said the necessary care and support would be provided to the students involved “to help them reflect on and learn from their mistakes”.

“We are disturbed by these developments and care deeply for the welfare of all our students,” he wrote. “We hope Hong Kong society can offer them a chance to recover from this regrettable episode. We also have faith in the integrity of our legal process in dealing with this matter.”

Speaking on the sidelines of a Legislative Council meeting on Wednesday, Secretary for Security Chris Tang Ping-keung dismissed concerns that the arrests constituted part of a wider crackdown on critics of the government.

“[Some people said] they are just students, why are you accusing them? But everyone has to pay the price for breaking the law. If [you were a student when] you broke the law, the court can decide whether that’s a mitigating factor,” he said.

“If you have committed an offence, there’s no excuse. Whatever your background, whatever your profession, we will do it fairly and impartially in accordance with evidence.”

Disbanded teachers’ union, protest organiser warned they can still be investigated for crimes

Tang was also asked by lawmakers how authorities planned to tackle terrorism in general.

He said “local radical groups” had recruited members on social media using similar tactics employed by international terrorist groups. Dedicated police teams would enhance online monitoring and use artificial intelligence to help identify suspicious messaging, he added.

Under Article 27 of the national security law, anyone convicted of advocating terrorism or inciting terrorist acts faces a mandatory sentence of five to 10 years.

Commenting on the arrests earlier in the day, Chief Secretary John Lee Ka-chiu said police had a duty to act when the city’s laws were violated.

“It is important that we develop a law-abiding culture, which at some stage has been destroyed by the violence since 2019,” Lee said.

“At this time, when we have to rectify the incorrectness, we must ensure that this principle of being a law-abiding citizen is the fundamental cornerstone for a city to be stable and prosper.”

‘Lone wolf terrorist’ attack leaves assailant dead, police officer in serious condition

Amid the furious backlash to the students’ motion, union president Kwok back-pedalled the next day, saying he believed the resolution to be “extremely inappropriate”. Some of the student leaders also apologised and stepped down from their posts.

On July 16, national security police raided the union’s office as part of an investigation into whether the group had advocated or incited terrorism, according to a source from the force.

At his press briefing, Li also confirmed that police had decided to refer the July 1 stabbing case to the Coroner’s Court.

Additional reporting by Natalie Wong and Cat Wang