Two women have been killed and detectives realize there's a similarity in dress to a missing woman. As they narrow down what the women look like and how the environment is when they're killed, more are killed and they find more people likely to be the killers. The problem is that they torture them, so of course they confess. Then it turns out they couldn't be the murderer. The detectives become more desperate (and they don't take the ideas of the female officer, who turns out to be right in a number of cases) and in the end, can't make their final suspect confess, even though 10 women have been killed and mutilated over six years.
In 2003, one of the previous-detectives is driven by the second murder site -- he now sells juice extractors -- and has his driver stop. He looks down in the trench and a little girl comes by and asks him why he's there. He says he'd been there before and just wanted to look. The little girl says another man came by recently and he said he came back because he'd done something there. But the previous detective can't get her to describe her face.
There was a lot of violence and foul language in this, plus a bit of sex and sexual description. I was looking for news of the time, but instead found an excellent review from the New York Times. It really is a good movie, but settle in for unpleasant actions.