1x11 - Psychopath Diary

Bo Kyung starts having doubts about Dong Sik being a nice guy and attempts to get a sample of his DNA. Dong Sik, who is agonizing over the fact he killed Park Moo Suk, returns the million dollars to In Woo and decides to leave town. However, as Dong Sik leaves town, he soon realizes that he left the red diary at the restaurant he was at with In Woo.