The Lost Soldiers by Andrei Kurkov

Fresh from case of the stolen heart, one that shattered his belief in the regime he works for, Samson Kolechko is confronted with a mystery that borders on the impossible. How could a squad of Red Army soldiers have disappeared from the Galician bathhouse, leaving only their boots and their uniforms as evidence they ever existed? Faced with such a fantastical conundrum, Samson resorts to fantastical investigation method: stitching his operative severed ear into a bathhouse worker's jacket, he is able to eavesdrop on his every move. But he discovers far more than he bargained for, uncovering human remains in the stoves and the presence of a sinister religious cult in the city. With his quick-witted new wife Nadezhda at his side, Samson must not only solve the case but navigate the political turmoil that still grips Kyiv as civil war looms and trust between neighbours and comrades is eroded day by day.