Episode 18 S01 E18

Jeong In-gi (as Cha Do-hyeok) Jo Min-jun (as Lee Hyung-nyeon) Yoon Sang-hyun (as Ha Moo Yum) Kim Min-jung (as Maria Oh) Sung Dong-il (as Yang Cheol-gon) Lee Joon (as Ryu Tae-oh) Kim Ji-won (as Ma Ji-wool) Kang Nam-gil (as Han Sang-hoon) Min Sung-wook (as Nam Ki Ri) Yoon Kyun-sang (as Youngest detective) Choo Soo-hyun (as Oh Young-ae) Yoon Chan-young (as young Ryu Tae-oh) Hyun Woo (as young Cha Do-hyeok) Ha Jun (as Nah Do-Hyung)

detective investigation psychopath murder serial killer mad dog