Psychological/mystery anime?

[RichardMoore]

I just finished watching Monster, which was a very enjoyable anime. One of the things I liked about it were the moral quandaries presented, the thick tension, the unbelievably evil villain (we're talking Joker without the make-up), and the lack of supernatural elements.

I also like Detective Conan, which doesn't get as dark as Monster, but still presents a compelling mystery without supernatural elements (albeit the shrinking drug).

Is there any anime similar that has deep psychological undertones, compelling characters, lack of mecha, spirits, or magic, and is good?