Who Killed Cock Robin (Mandarin: 目擊者, lit. "Eyewitness") is a 2017 Taiwanese neo-noir crime thriller film, written and directed by Cheng Wei-hao. The film follows a journalist who unravels a series of mysteries as he investigates a long-forgotten hit-and-run accident that occurred nine years ago. It also marked Cheng's second collaboration with Hsu Wei-ning, after The Tag-Along. The film also stars Kaiser Chuang, Ko Chia-yen, Christopher Lee and Mason Lee. It was released on March 31, 2017, in Taiwan.