after the second murder, the investigation was taken under special control by the procurator general of the soviet union, who established that the perpetrator did not leave any fingerprints or semen at the crime scene. at the second and third murder site, the killer had torn the passports of his victims in order to further complicate their identification. the actions of the offender made the police assume that he was previously convicted. the suggestion was confirmed when they found a witness who saw a tall guy on a construction site near dinamo metro station with a dark spot on his lower back (the witness had noticed a tattoo when raevsky was wearing a t-shirt). the tattoo on the lower back brought the investigators to the idea that the killer was abused during detention. verification of criminal records, including reports of escapes from prisons, made it possible to identify raevsky.