Time Limit Investigator (2006)

Shūichirō Kiriyama works at the Limitation Task Force, the place where the cases which have reached the statute of limitations are destroyed. Getting bored of his job, he decides to find a hobby, because it seems important to him to have a hobby. So he decides to puzzle out the unsolved cases on his free time, helped by his coworker Mikazuki, who seems to have a crush on him.