If you love detective stuff, crime and thrills, Tantei Gakuen Q is for you.

The stories are nothing short of amazing and you'll have to rack your brain to solve them yourself. The crimes are good(I mean really good), the detectives are good and the plots are better.

The character developments are subtle but good, and Ryu's growth is certainly a marvel. Romance is a bit light here(what do you expect from a detective manga, eh?) and so is the art. But the story makes up for all the flaws.

If you liked the anime, then definitely read the manga, it's just loads better.