Using DNA to track down a suspect
21 crimes, 21 instances of DNA being found at the crime scene, one perpetrator. For ten months, he was on the move in eastern Switzerland and Liechtenstein, committing one burglary after another. Thanks to Europe-wide cooperation, he was finally identified.
From March to December 2023, 21 burglaries in Eastern Switzerland and the Principality of Liechtenstein were apparently committed by the same person: in Zurich, St. Gallen, Vaduz, Winterthur and many other towns and villages. The police records indicate there were burglaries in apartments, houses and offices, committed mainly in the evening and at night.
Was any evidence left after the break-ins? Doors and windows were drilled open. There were no fingerprints or handprints – gloves were probably used. But perpetrators always leave some trace, if only a strand of hair or skin cell. Several dozen of the crime scene samples analysed by the police were sufficient to produce DNA profiles. The analysis revealed that the DNA found at the various crime scenes was from the same male individual. However, a search in the national CODIS DNA database showed that the individual was not yet known to the police in Switzerland.
«Biometric data are unique to a person and therefore decisive in identifying the perpetrator. Whether it’s a fingerprint, DNA profile or facial image – our job as police is to put these pieces of the puzzle together to form a coherent overall picture in order to solve crimes.»
Axel, head of the Biometric Identification Section
At the request of the Zurich cantonal police, fedpol sent the DNA profile to foreign partner authorities via INTERPOL on 30 May, asking them to run it through their national DNA databases. The Carabinieri in Rome reported a match with an individual who already had a criminal record in Italy. fedpol then ran the DNA profile from Italy through the CODIS DNA database and found a full match between the DNA profile provided by the Carabinieri and the 21 DNA profiles obtained from the crime scenes.
The person whose DNA was found at the scene, the prime suspect, now had a name!
Prüm Convention
Swiss law enforcement authorities currently request information on DNA profiles and fingerprints from foreign authorities via INTERPOL. The request is sent to each country individually. There is no guarantee of a prompt response. This is set to change thanks to the Prüm Convention, under which a single query will trigger an automated database search in all the requested EU countries. In future, fedpol will receive information within 24 hours with just a single request: does any country have any useful information about this specific case?
But there was a catch: the Carabinieri had neither the fingerprints nor photos of the suspect. fedpol then sent the DNA profile to the police authorities in Albania, the suspect’s country of origin, and found another full match. The INTERPOL National Central Bureau in Tirana reported that the suspect was already known in Albania for burglaries and provided a photograph from a previous investigation.
The suspect now had a face.
On 20 December, the St. Gallen cantonal police arrested the suspect. Before his forays into Switzerland, he had already been active in northern Italy while part of a criminal gang. The suspect is now on remand, and will not be breaking doors and windows open for the foreseeable future, or certainly not with a drill.