Globally, it is estimated that over 1 billion people live with severe disabilities, requiring attendant care, and are estimated to be disproportionately victims of physical abuse, often by caregivers or attendants. In Italy, approximately 19.4% of the over 3 million severely disabled people are victims of physical abuse by their caregivers. This study is based on a real case, and it aimed to evaluate touch DNA deposition on nitrile gloves during either an innocent caregiving activity or a simulated strangulation. A total of ten volunteers, comprising both male and female participants, were selected for the study and divided into pairs, with each participant acting as both the caregiver (CG) and the care recipient (CR) once. For the caregiving scenario, the CG was instructed to rub the CR’s upper arm. To simulate the act of strangulation, the CG squeezed the CR’s upper arm. In both instances, the CG wore nitrile gloves and performed the disputed action, with both hands, for a duration of 30 seconds. Each scenario was repeated three times for each CG-CR pair in order to account for individual shedding propensity variability. The external and internal surfaces of the gloves were separately sampled using a moistened single cotton swab. The samples were extracted with the phenol-chloroform organic method and quantified with the PowerPlex® kit. STR typing was performed with the ESX17 Fast kit, fragment separation was carried out on the SeqStudio Genetic Analyzer™, and data analysis was performed with GeneMapper® ID-X v 1.6. The strength of the evidence for both CG and CR was evaluated with EuroForMix v 4.0.1, and their relative contribution in terms of DNA quantities was assessed. Results demonstrated that, for short-term wear, a greater amount of both the CR’s DNA (external surface of the gloves) and of the CG’s DNA (internal surface of the gloves) was recovered during the caretaking activity, in comparison to the strangulation scenario. This discrepancy could be ascribed to the friction generated by the rubbing motion performed during the caretaking activity, thereby increasing DNA transfer. The static pressure exerted by the CG, in conjunction with the experimental constraints of replicating the disputed action without inflicting harm to the participants, may have both contributed to the observed reduction in DNA amounts. Unknown, foreign DNA was detected in approximately half of both the caregiving and strangulation samples.

Authors

• Martina Onofri (Section of Legal Medicine, Department of Medicine and Surgery, University of Perugia, Italy)
• Federica Tommolini (Forensic Sciences Laboratory, Section of Legal Medicine, Department of Medicine and Surgery, Santa Maria Hospital, University of Perugia, Italy)
• Simona Severini (Forensic Sciences Laboratory, Section of Legal Medicine, Department of Medicine and Surgery, Santa Maria Hospital, University of Perugia, Italy)
• Sarah Occhino (Forensic Sciences Laboratory, Section of Legal Medicine, Department of Medicine and Surgery, Santa Maria Hospital, University of Perugia, Italy)
• Eugenia Carnevali (Forensic Sciences Laboratory, Section of Legal Medicine, Department of Medicine and Surgery, Santa Maria Hospital, University of Perugia, Italy)