Innocent Grey - Cartagra ~Tsuki Kurui no Yamai~

The hero of this story is Takashiro Shugo - an ex-police officer, now unemployed and freeloading at a brothel. From time to time he takes on detective work from his former superior.
A missing persons case is dumped onto him one day. Kohzuki Yura... the girl he had an intimate relationship with before being sent off to war.

A brutal series of killings begins. As they occur closer and closer to home, Shugo can no longer turn a blind eye, and is dragged into the spiraling web of missing people and murders.