Identification of burglars using foil impressioning based on tool marks and DNA evidence.

In burglary cases, the skeleton keys used by burglars often leave tool marks that can not be identified. Hence, forensic trace experts can only provide investigating authorities with useful information by categorizing the lock opening method of pin tumbler lock cylinders and defining the class characteristics of the tool used. It is important to note that as per the standard processes, expensive and more time consuming DNA-tests may not be applied to this evidence type. During the past few years, more and more dimple locks were documented by the police being removed from security doors at burglary scenes and sent to the Hungarian Institute for Forensic Sciences. These dimple locks were made in China with no brand mark, with 6-8 pin tumblers. We noticed previously unknown tool marks on the horizontal keyway, on the face and on the side of the tumblers of most of these dimple locks. We also found fragments of aluminium foil in the bottom of the plugs. Based on this, we came to the conclusion that the burglars work with a new method when opening this type of locks, which required forensic trace experts to introduce a new way of examination. In this study specific data is meant to be presented supporting the observations above. This paper is presenting a new lock opening method and the tool marks left behind. Our purpose was to develop a new method which takes the benefit of a new type of evidence: foil fragments noticed in the cylinder with possible DNA evidence, which was previously unknown by the police. This goes beyond the scope of general investigative findings, allowing a more effective identification of the burglars. We are also going to explicate the results of our DNA tests. Foil fragments having been recorded under sterile conditions brought searchable DNA-profiles in 52 % of the cases. In 55 % of these cases DNA-profiles were matched with suspects' and a series of crimes and groups of criminals were explored. Examining the DNA-profiles that did not match suspects' profiles revealed the presence of victims' DNA in certain cases. The outcomes of our study highlight that collecting victim DNA-samples should be implemented as a default process in cases where a DNA-test is required.