Storm in a Glass of Misery

The 53rd book in the series "Viola Tarakanova. In the World of Criminal Passions".

Here’s a tough problem for you, Vilka. Solve it instead of working on repairs.
Matvey Grishin’s one of the twin daughters fell ill. During the treatment and tests, it was revealed that he is not the biological father of the girls. But this just cannot be true! The shocked man eliminates the idea of his wife’s infidelity: Verusya and Natusya are his exact copies: dark-skinned, dark-haired, brown-eyed... Grishin asks Viola to investigate this matter and clarify everything.
His head is spinning from these twins! Vilka and Stepan began to dig out skeletons from the closets of this strange family and uncovered... a doppelgänger of Matvey, a certain Boris Bogdanov. And just as the solution to the mystery was emerging, Boris is found dead. The case takes a rather serious turn.