Judge Clement Lee said video footage showed that Cheung Chun-ho, 20, and Tang Hei-man, 24, were among around a hundred people who breached the peace – by throwing bricks and molotov cocktails towards the police – at a bridge outside the university campus on November 12.
The judge said the only reasonable conclusion was that the two had been taking part in the riot when the police were being attacked.
The court heard Cheung studied at the Institute of Vocational Education and Tang studied at Chinese University.
But the court acquitted Chan Hey-hang, 22, and Lee Chun-ho, 25, ruling that there was not enough evidence to show how long they had stayed “at the centre” of the riot or whether they were there at all.
Chan studied at Chinese University and Lee studied at Polytechnic University.
The court also rejected the testimony of a police officer who arrested Chan and Lee as it was in conflict with video evidence.
Cheung, Tang, and Chan were also found guilty of breaching the mask ban in place.
The defence had said the trio were trying to protect their health by wearing gas masks, but the judge said they should have just left the scene as soon as possible if that was the case.
Meanwhile, the court found Cheung not guilty of possessing an offensive weapon. The judge pointed out that the police had only found a laser pointer and scissors in Cheung’s bag the second time they checked it, saying this was a flaw in the prosecution’s case.