1. Fragmented information
Cases were discovered at different times and in different jurisdictions. Missing-person reports, local crime records, and forensic findings did not automatically form one unified picture. Linking cases required sustained coordination.
2. False leads and unreliable confessions
Investigators questioned many people, and coercive interrogation practices in the Soviet system contributed to false confessions. Alexander Kravchenko's wrongful conviction and execution in the Zakotnova case illustrates the human cost of accepting a confession without sufficiently testing it against the evidence.
3. An overly decisive forensic exclusion
Blood-group evidence was treated as if it ruled Chikatilo out. The inference was flawed because he was a “non-secretor”: his blood group could not reliably be inferred from bodily secretions in the way investigators assumed. His blood typed as A, while the semen evidence was interpreted as AB. This was a major reason he escaped the murder investigation in 1984.
4. Limits of the era's forensic science
Modern DNA profiling was not available to investigators in the form used today. The case relied on conventional forensic analysis, witness accounts, surveillance, geographic and behavioral patterns, and later the suspect's statements and their corroboration.
5. Profiling as a lead—not proof
Aleksandr Bukhanovsky's profile helped investigators conceptualize the offender and later engage Chikatilo in conversation. Behavioral profiling could focus an investigation, but the identity and charges still had to be tested through evidence.