Intelligent, pretty cold character study of a French serial killer of young girls that, unfortunately, only took stabs at the surface without digging deeper into the meaningful material. The casting is excellent with Guillaume Canet's performance as the exemplar Gendarme with sociological issues is both chilling and convincing.

A serial killer who at the same time is a law enforcer, helps to investigate his own crimes. That's the subject of this French thriller, based on a true story. The killer seems to be beyond suspicion and knows all the tricks in the book not to get caught. This leads to bizarre episodes: the policeman's face perfectly resembles the police sketch of the presumed killer, but even when he confronts possible witnesses with the sketch, nobody gets alarmed.

The film makers not only tell the crime story of how the killer eventually gets caught, but also highlight the Dr Jekyll & Mr Hyde-personality of the policeman (or gendarme to be more precise). The killer is a ruthless psychopath, but when he is dressed in his uniform he is a polite, hard working and scrupulous man.

So this film is half thriller, half psychological drama. In my opinion, this works well. The director gradually builds up the suspense: more and more elements are found to reveal the identity of the killer, and as a viewer you see the net around him slowly tightening.

The film is set in 1978, and the period details are very nicely done. Since there is a lot of driving around, the film makers had to use lots of French cars from that era.

This is a nice thriller, in the style of the famous French 'policiers', with an intelligent screenplay and interesting character development.

Intelligent, frosty character study of a French serial killer of young girls, based on a real case from the 1970s. The super dark anti-hero is played with great subtlety by Guillaume Canet, and the film is very well shot.

But there's a last layer missing that keeps this from going from a very good film to a great one. As much as it's always interesting, and sometimes even heartbreaking, there's a lack of larger theme or context that keeps this confined to being a thriller/character study - if a very intelligent and thoughtful one - and not the rare film that transcends into something even larger.

But it's still very worth seeing as a study of a brilliant but tortured man compelled to horrible violence, and on 2nd viewing I found it a more powerful and emotional experience, catching details and moments I missed the first time around.