Change the World: Kyou Kara Satsujinki

Saito Yuichi, a self-proclaimed social reject, has accidentally switched bodies with an elite police officer, Mitsumune Sakutaro! He still has his consciousness, but his body is completely different. Now with a whole new life ahead of him, he thought he could enjoy being an elite detective. But it seems that his new body is hiding a few important secrets!
(Source: INKR)