Two secondary school students also taken into custody; incident occurred after police halted Chater Garden rally in January
They came to pay tribute to Chow Tsz-lok, who died of a brain injury after falling from a car park in November.
The weekend also saw an early morning petrol bomb attack outside a respiratory infection clinic, as dozens demonstrated outside medical facilities
The demonstration was originally organised by the Civil Human Rights Front, who cancelled it when police objected, but protesters still gathered in Central
Netizens have been encouraging internet users to support the 'yellow YouTube circle' as part of the pro-democracy movement.
Video footage showed three people lighting the bombs while hiding behind flower beds outside Kwai Fong Plaza
A forum user posted the idea of sharing made-up stories to negatively impact mainlanders' support for the Chinese government.
Former head of the IPCC said it was unfair to burden the watchdog with the role, and supported the call for an independent commission of inquiry.
Hundreds of people gathered to commemorate the event and express their continued disappointment in police's handling of the incident.
Commissioner calls for tougher laws and more powers for watchdog to tackle 'weaponising' of personal data.