Mitsuhiro works with Keiichi Ikari in the Metal Bat case, and is often the more understanding of the two. He has a very gentle personality and questions Keiichi's hastiness in his mind. It is thanks to Mitsuhiro that they've been able to get through to many of the witnesses and victims of Metal Bat's attacks.

Spoiler

He is the first to see the pattern among the victims, and to realize that the Bat can appear in two places at once.

(Source: Paranoia Agent Wiki)