Matantei Loki RagnarokThe Mythical Detective Loki Ragnarok - Kinoshita, Sakura

Private Investigator Loki is certainly an extraordinary fellow with an incredibly demanding profession. While his boyish good looks disguise his true nature, no challenge is too tough for Loki. Not only is it Loki's job to solve mysteries, but he must also protect his own interests, namely his family, especially when those who want him rubbed-out enter the picture. Loki must dig up evidence surrounding kidnappings, murders, suicides, and the like. When old adversaries strike too close to home, Loki must prepare, not only to solve the crime, but to survive the vicious attacks! If the action's hot, you can count on Loki being there!
(Source: ADV)

Matantei Loki Ragnarok had four volumes released in English as The Mythical Detective Loki Ragnarok by ADV Manga from October 4, 2004 to August 1, 2005 before the license was dropped and the publisher went defunct.