My opinion is the SERIAL KILLER IS REAL BAEK HAE SUNG i can see it from the eyes. But that time he must be young like DO HAE SUN AND DO HYUN SU. it must be because his parents too perfect raise him so he stressed. Remember when Baek Hae Sung mom told Baek Eun Ha to not doing math book because it makes you crazy. I think REAL BAEK HAE SUNG is like that.
Yes, i think the same way , the real Baek Hae Su is the killer from his eyes. But what i want to know the most is why His Father make him coma , why? and why he ask Do Hyun Su to be his son since he know it will be risk both of their life.
I have a feeling that the real Baek Hae Sung is the real culprit Since he's psychopath because he's under pressure from his parents. And his parents know it so his dad make him coma like that? if he want his position as director