The case “Erika H.” serves as a prime example of how old evidence becomes susceptible to DNA contamination due to repeated testing, transfers between agencies, gaps in historical documentation and a lack of protective clothing. A supposedly relevant DNA match created a link to a second homicide. Only after a painstaking reconstruction of the evidence’s path did it become clear that both traces had already been processed in the same laboratory in 1981; the match could ultimately be attributed to a case worker from that time. The problem is structural: The current elimination-database records only a portion of the staff and deletes profiles upon termination. As a result, cold cases lack effective protection against historical false leads. A “BlackBox” is therefore proposed, which would retain deleted profiles without personal identifiers for long-term comparisons.

Authors

• Ezgi Sari (LKA Rheinland-Pfalz, Germany)
• Stefanie Grethe (LKA Rheinland-Pfalz, Germany)