sentences:  Tulipov goes back to the graveyard to interview the people who attended Izhitsin's experiment, and, in a sudden fit of inspiration, believes he's figured out who the killer is.While Tulipov is pursuing his theory, the Decorator arrives at his apartment and kills his sister Sonya.Fandorin is informed of this, and is then given a deathbed report from Tulipov, who believed the killer was Zakharov and had gone to Zakharov's office at the graveyard to observe him—only to run into the Decorator, who attacked and mortally wounded him.