Kohaku-iro no Yuigon

Kohakuiro no Yuigon ("Amber Testament") is the first in the row of detective games starring the fictional Japanese private investigator Ryūnosuke Tōdō. The events of the game take places in Japan in the year 1921, and Tōdō must investigate a mysterious murder of a rich man in his own mansion. The deceased had many relatives, and its the detective's job to find out which one of them (if any) has committed the murder.

[From MobyGames]