This documentary shows in different perspectives the motives behind Korea's first serial killer. Many police officers, profilers, detectives and the victim's family members take part in describing the motives and the methods behind the most important murders but also the pain suffered by the families and the new investigative methods that the police learned after this case.
The documentary makes a good job in describing the psychology of the murderer and the lack of remorse he had after being apprehended.
What's really nice is how they simulate or act the different scenes told by the people involved, it really helps to see the extent and atrocities made by this criminal.
Nevertheless, this documentary could have one more episode showing how the police investigated the other cases and what have they worked out to catch him. It left the impression that the police was just lucky in catching him the first (and even the second) time.