The Winter Queen (Erast Fandorin, Bk 1)

Moscow, May 1876. What would cause a talented student from a wealthy family to shoot himself in front of a promenading public? Decadence and boredom, it is presumed. But young sleuth Erast Fandorin is not satisfied with the conclusion that this death is an open-and-shut case, nor with the preliminary detective work the precinct has done -- and for good reason: The bizarre and tragic suicide is soon connected to a clear case of murder, witnessed firsthand by Fandorin himself. Relying on his keen intuition, the eager detective plunges into an investigation that leads him across Europe, landing him at the center of a vast conspiracy with the deadliest of implications.

Translated from the Russian by Andrew Bromfield.
Boris Akunin, pseudonym of Grigori Tchkhartichvili