Chief Superintendent Tse Chun-chung of the Hong Kong Police Public Relations Branch (PPRB) shows an evidence image of violent acts by radical protesters during a press conference in south China's Hong Kong, Sept. 9, 2019. The Hong Kong police said on Monday that a total of 157 people had been arrested for violent acts in different parts of Hong Kong from Friday to early Monday. (Xinhua/Lu Hanxin)