Chul Gon arrests Mu Yeom after he is found at the scene of the second crime. Maria asks her stepfather, the primary profiler on the original Gap Dong case, his opinion on Mu Yeom's involvement. Maria learns that the patients believe that "Oh Maria belongs to Gap Dong" and investigates as she begins to be taunted by Gap Dong's whistle. Police officials admit to a secret when Chul Gon attempts to use DNA evidence to prove Mu Yeom's guilt .