Zodiac
I think why I love Zodiac so much and dislike a lot of other 'true crime' media that have popped up in recent years is because it focuses so much on the human aspect of the case.
It's not just a movie about the Zodiac killer, it's a movie about how the public's fixation on the case ultimately hurt so many people. It looks at the lives of the people working on the case and shows their slow but inevitable spiral into obsession over the case.
It focuses equally on what the Zodiac killer did, and how the Zodiac affected the lives of the people he didn't even attack.
And it's such a Fincher thing to do to spend so much time on the people rather than just the killer.