Amber Poon Hiu-wing, a 20-year-old pregnant woman from Hong Kong, was killed in Taipei on 17 February 2018 whilst on vacation with her boyfriend Chan Tong-kai, aged 19 at the time and from Shenzhen. Chan admitted to Hong Kong authorities that he killed his girlfriend in a hotel room in Taipei, stole her belongings, left her body in the bushes, and flew back to Hong Kong. As the murder happened in Taiwan where they had no jurisdiction, the authorities in Hong Kong could not charge Chan with murder, and could only sentence him on money laundering charges resulting from the killing. Chan could not be extradited to Taiwan either since there is no extradition treaty between Hong Kong and Taiwan.
Organisers estimated nearly two million protesters took to the streets calling for the full withdrawal of the extradition bill on 16 June.