The Detective 2 (2011)

Private detective Chan Tam finds himself in over his head when his friend, police officer Fung Chak, recruits him to assist with a perplexing serial murder investigation. The case involves a middle-aged man murdered in his home, a woman discarded in a trash dump, and a teenage girl found dead in a park, each victim killed in shocking ways that appear unrelated. Struggling to piece together the evidence and with no leads to pursue, Tam feels increasingly overwhelmed and desperate for answers.