Residential burglaries often go unsolved, as collected DNA traces and fingermarks frequently originate from residents rather than the offender. It is therefore important to know how to target sampling locations that specifically relate to the burglary event. However, data that aid in assessing the likelihood of a burglar touching certain surfaces, and, consequently leaving trace evidence, is unavailable. Instead, forensic examiners rely primarily on their personal experience and expertise to determine where burglary-related traces are most likely to be found.The current study aims to identify specific areas that are contacted during different types of interactions with points of entry. An experiment was conducted at a Dutch music festival, where participants simulated both a legitimate and burglary scenario. Using paint, the points of contact between the participants’ hands and the experimental set-up were recorded. The contact locations of all participants were combined using heatmaps to reveal the patterns of contact. We found that different burglary methods lead to distinct contact patterns, indicating specific areas where traces are most likely to be deposited. Our findings can support forensic examiners in making evidence-based decisions during search strategies in burglary investigations.
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Selecting the most successful and relevant traces at the crime scene is of the utmost importance as irrelevant traces may take up valuable capacity, increasing the risk that cases remain unsolved. In order to ensure that most relevant traces are collected, knowledge is required regarding how and where forensic traces are deposited given the activities being considered in the case relevant scenarios. As of now, however, this knowledge is limited. While studies on the transfer, prevalence, persistence and recovery of trace materials are becoming more common, most of such studies focus on crime centered scenarios and often do not take alternative, innocent, scenarios into account. Moreover, these studies often focus on specific objects or small spaces such as offices or vehicles. With the project No trace to waste (start: January 2023), we aim to extend the knowledge on trace dynamics as a strategy to improve the search for and selection of most relevant and successful traces. Throughout the project, the focus will be on DNA and fingermarks within home environments, as burglaries and home invasions remain common offenses and can be considered highly impactful on the victim’s lives. During the first phase, the distribution of traces given certain scenarios is investigated. Test subjects are asked to simulate various, both innocent and crime-related, activities within the model homes of the Dutch Police Academy. A fluorescent tracer is used to determine the objects/surfaces which the test subject has been in contact with and thus, where trace material could be expected to be deposited. Using these findings, the project moves onwards to investigate the persistence and transfer of actual traces during social settings, the prevalence of residents’ own DNA and fingermarks in the average active home and how these influence the recovery of crime-related traces post-offense. Finally, the project aims at supporting the forensic practitioners of the future. The knowledge obtained will be used to evaluate how to improve current practices and professional education. This in turn will support forensic practitioners on-scene with the selection of relevant traces and sampling locations and allows for a more efficient use of the available capacity and resources.
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