Identification by digital image superimposition of body parts : a case report

Image identification is nowadays a common request in forensic practice and direct digital image superimposition can be considered a valid technique for establishing identity. This procedure applied in forensic sciences is not only limited to facial identification but also to other body parts. The authors present an unusual case where the judge requested personal identification on digital images of body parts of a living woman which did not include the face. A young wife, after two violent domestic quarrels with her husband, took some digital snapshots of her upper and lower limbs of the neck with fresh, nonpatterned contusions and abrasions caused by blunt force trauma years before. These images were preserved and used a few years later, during a troubled legal separation, just to show that the self-claimed kind husband “was not really such a lovely spouse during the last period of their marriage”, whereas the husband affirmed that the body parts in the digital snapshots belonged to his mother-in-law and not to his wife. The digital images proposed for evaluation to the forensic expert were taken in the conjugal house, well recognizable by furniture and others personal domestic objects, and were all self-made photographs which included only the body parts of a woman with blunt trauma injuries, with only a very limited part of the face visible. The identification process begun with a forensic examination of the young woman (2008), wearing the same black wool dress, with an analysis of peculiar, legible, time-stable individual traits, present in the photographed body parts: melanocytic nevi, scars, telangiectases, nasolabial sulcus. The technical procedure chosen for identity verification was digital image superimposition, therefore new digital photos were taken, approximately in the same anatomical areas and geometric conditions. Of the original series only good quality snapshots, with well visible distinctive features, were considered for comparison. In order to express an identification judgement via digital superimposition it is not sufficient to project the actual photos onto the original series, resizing, reorienting and repositioning them via specific softwares, but a complete forensic examination with recognition of unique morphological factors must be guaranteed for a correct identification procedure. Melanocytic nevi in the adult period can be considered substantially time-stable in pattern and structure. The possible solar induced nevogenesis, in such a time period (four years) could be not excluded but the various and different body parts (upper and lower limbs, part of the chin) present in the images allowed us to identify the same pattern of distribution and nevi size; nevi regression may be excluded by the woman’s relatively young age. Additionally the presence of a surgical scar on the left knee and telangectasia on the left lower limb, led to a positive identification. The case presented reaffirms the need for caution in managing new identification tools in biological matters that always need a complete and exhaustive forensic evaluation, even if the solution may seem to simply proceed with a software-aided superimposition.