The Death of Achilles by Boris Akunin

In 1882, after six years of foreign travel and adventure, renowned diplomat and detective Erast Fandorin returns to Moscow in the heart of Mother Russia. His Moscow homecoming is anything but peaceful. In the hotel where he and his loyal if impertinent manservant Masa are staying, Fandorin’s old war-hero friend General Michel Sobolev (“Achilles” to the crowd) has been found dead, felled in his armchair by an apparent heart attack. But Fandorin suspects an unnatural cause. His suspicions lead him to the boudoir of the beautiful singer–“not exactly a courtesan”–known as Wanda. Apparently, in Wanda’s bed, the general secretly breathed his last. . . .