Before I start my review, I would like to clarify a few things.

1. This crime focuses on Behavioral Crime Unit that focuses on perpertrators' mind and psychology. So it does not focus on finding physical proofs like most crime dramas, nor does it depicts much on how they catch the perpertrators.
2. This drama has a lot of talk than actions, in my opinion. So if you are the type of a person who likes action i.e running and fighting from the main characters' part, this is not for you.
3. This drama is based from the non fiction book by South Korea's first profiler, Kwon Il-yong. Therefore, the cases are based on real cases (for example, Yoo Yoon Chul) and the main character is loosely based from Kwon Il-yong himself. He also acted as this drama's advisor to make sure the details are correct.
4. I suggest you watch the Raincoat Killer documentary on Netflix to have a better understanding and appreciation of this drama. I helped me tremendously.
5. Trigger warning to those who can't watch crime against little children, violent killings and psychopaths who have no remorse in whatever heinous crime they commit. There're mentions about children raping and abuse too. just fyi.

Alright. Now that we have cleared all those things up, I would have to say, as a person who once taken psychology as one of my subject in uni, a diehard fan of Criminal Minds (US tv series) and the likes, I would have to say this drama is GOLD. These are my reasons:

PLOT
The fact that the cases are taken from real cases is just a plus point for me. The cases are gruesome that makes you wonder if the world is about to end because these psychopaths exist. I even cried because one of the cases that involved a little girl. Damn. That got me deep.

ACTING
The cast lineups are chef's kiss. We have Kim Nam Gil, Jin Seon Kyu and Kim So Jin. These are spectacular actors. The brought the character to life. Nam Gil for me shoud reveive an award for his acting here. His tortured facial expression when he interviewed the criminals was just.... I'm speechless. Then there were the actors who acted as the criminals. Oh. MY. GOD. Standing ovasion from me. If I were the wife of one of them, I may want to sleep seperately for a week because their acting were damn real it gave me chills.

You know what, I'm just gonna stop here. Just watch because of these two reasons. It's enough for you to be glued for the whole 12 episodes. Kudos to them team who made this masterpiece.

For others who like this type of drama, I suggest you watch Criminal Minds (US version. Korean version sucks. Don't get me start on that), Mindhunter (tho it's a bit slow and has faaarrrr more talks than action) and Criminal series on Netflix (UK version. The other version were just okay. UK version is best among all).

Aite. That's all. Hope this review is helpful. ✌🏼