Question: What is 2015 South Korean slasher-thriller film directed by Hong Won-chan and starring Go Ah-sung and Park Sung-woong, that starred a a South Korean actress who began her career as a child actress?
Sentence (from "Office (2015 South Korean film)"): It is about a detective trying to figure out why a mild-mannered man has killed his family and is targeting his co-workers.
Relevant evidence: No