Signal Season 1 Episode 4
Overview
The cold case squad figures out who the serial killer is, but not before the wrong suspect turns himself in.
Director: Kim Won-suk
Guest Star: Hong Seok-bin, Kim Jung-young, Kim Ki-chun, kim-ki-cheon, Lee Do-yeop, Lee Ki-sub, Lee Si-a, lee-gi-seob, lee-ki-seop, lee-xia, Nam Sang-ran, Oh Jin-ha, Sung Hyun-mi