Convictions and jail

In 1998, Koo, along with Tsang Kin-shing, Leung Kwok-hung, and Lau Shan-ching, was fined HK$3,000 for disorder in public spaces over burning mock coffins during the visit by Jiang Zemin, paramount leader of China.

In 2000, Koo was jailed 14 days over two protests during Legislative Council proceedings.

In December 2008, Koo was accused of attacking guards of Legislative Council during protests against public offering of Link REIT, a real estate investment trust, and was jailed for 7 days after choosing not to pay the HK$2,000 fine.

On 18 February 2013, Koo was jailed for 9 months for desecrating the national and Hong Kong flags in protest at human rights abuses in China and the alleged murder of Li Wangyang.^[9] The jail term was reduced to 4.5 months on appeal.^[10] The same April, he was given a 4-month suspended sentence, reduced to 2 months on appeal, over attempt to burn the national flag at the Liaison Office.^[10]

In 2016, Koo was sentenced to 6 weeks’ imprisonment for having burnt the Hong Kong flag during the annual July 1 march in 2015.^[10] He celebrated his fifth jail sentence near the court.^[11][12]

On 27 March 2018, Koo was jailed for the sixth time, after desecrating the Chinese and Hong Kong flags during a candle light vigil in memory of Nobel Peace Prize winner Liu Xiaobo in 2017, and during the Chinese National Day protest in 2017, and New Year march in 2018. He was sent to 2 months in jail before chanting "all hail democracy", "all hail human rights" and "say no to the Chinese Community Party".^[13]

On 25 June 2019, Koo was jailed for six weeks after desecrating the Hong Kong flag by writing "Shameful Hong Kong Government" in protest against disqualifying Lau Siu-lai's MP seat, amounting to his seventh jail sentence.^[14]

On 28 January 2021, Koo received his tenth jail sentence of four months after desecrating the Chinese flag by writing "white terror" and "fascist horror" and flying it upside down, to voice out support with 15 democrats charged with illegal assembly. He vowed in court to breach the National Security Law imposed by China.^[15][16]

On 14 April 2021, just days after finishing his earlier jail term,^[17] Koo was jailed for 5 months over illegal assemblies with Joshua Wong on 5 October 2019, the day Prohibition on Face Covering Regulation was enacted.^[18]

Koo was again arrested on 4 February 2022, reportedly under the security law for suspected incitement of subversion, before his planned demonstration outside the Hong Kong Liaison Office to protest China's Winter Olympics and call attention to political activists behind bars.^[19][20] Facing charge of attempting to commit a seditious act over a one-metre long coffin and a white flag with language including "down with the Chinese Communist Party" and "end one-party rule" found at his home, Koo was denied bail. Koo was jailed for 9 months after the judge found him guilty.^[21]

On 18 December 2023, Koo was fined HK$6,000 for breaching fire safety regulations. The Hong Kong Fire Services Department had not informed him of their removal of his belongings from the open areas in an industrial building. Local media reported that he had been in hospital at the time of the removal.^[22]

On 16 February 2024, Koo was convicted to nine months in prison for "attempting or preparing to do an act with a seditious intention", after he was found guilty of planning a protest against the 2023 District Council elections.^[23]