Dark Figure of Crime
Believe but be doubtful.
Overview
A serial killer is caught for his seventh murder. A cop tries to solve the first six cases with the killer's help, but starts to suspect that he has ulterior motives. Based on a true story.
Trailer
Cast

Kim Yun-seok
Kim Hyeong-min

Ju Ji-hoon
Kang Tae-oh

Moon Jeong-hee
Kim Soo-min

Jin Sun-kyu
Detective Jo
Jeong Jong-jun
Chief of Crime Department

Heo Jin
Ji-hee's Grandmother

Kim Joong-ki
Lawyer

Kim Young-woong
Jeong-bong

Jeong Gi-seop
Detective Han

Kim Mi-hwa
Hair Salon Manager

Lee Bong-ryeon
Kang Sook-ja

Jeon Kuk-hwan
Hyeong-min's Father