A preliminary investigation of textile fibers in smothering scenarios and alternative legitimate activities. (October 2017)

• Record Type: Journal Article
• Authors: Schnegg, Michael; Turchany, Morgane; Deviterne, Marie; Gueissaz, Line; Hess, Sabine; Massonnet, Geneviève
• Is Part Of: Forensic science international. Volume 279(2017)
• Page Start: 165
• Page End: 176
• Publication Date: 2017-10
• Subjects: 1:1 taping -- Fiber distribution -- Fiber transfer -- Forensic interpretation -- Trace evidence; Medical jurisprudence -- Periodicals; Chemistry, Forensic -- Periodicals; Forensic Medicine -- Periodicals; Médecine légale -- Périodiques; Chimie légale -- Périodiques; Gerechtelijke geneeskunde; Gerechtelijke chemie; Gerechtelijke psychiatrie; Chemistry, Forensic; Medical jurisprudence; Electronic journals; Periodicals; Electronic journals; 614.1
• DOI: 10.1016/j.forsciint.2017.08.020
• Languages: English
• ISSNs: 0379-0738

Abstract

Highlights: Transfer of fibers in smothering and night's sleep activities was investigated. The shedding capacity of the donor fabric was the greatest influencing parameter. The distribution of fibers on the face was found to be relatively homogenous. Fewer fibers were transferred in simulations involving little movement. Fibre evidence can be used to discriminate against criminal and legitimate scenarios Abstract: Was this group of target fibers transferred during a criminal action? Is it possible that it was transferred during another legitimate activity? Acquiring knowledge about the activity, whether legitimate or criminal, leading to the transfer of a group of fibers is a recurring challenge encountered throughout the evidence interpretation process. Trace evidence such as fibers may assist with generating a reasoning of the activity which produced the trace, but this assumes that one already has a thorough understanding of the transfer phenomenon. How to generate and then use such relevant knowledge? What are the influencing parameters and which ones should (or can) be controlled? The present work focuses on homicides by smothering using a pillow and the transfer of fibers on the face of the victim in such events. A legitimate activity – represented by a night's sleep on a pillow – was also investigated since such legitimate, alternative explanations concerning the presence of fibers could likely be formulated by the suspect. The number and distribution of fibers transferred onto the victim's face in either scenario were investigated and interpreted using a Bayesian approach. Results showed that the shedding capacity of the pillowcase strongly impact the number of fibers recovered. The nature of the action, modus operandi and amount of friction could not be excluded in their influence on the transfer of fibers. Finally, likelihood ratios indicating the number of fibers recovered from the victim's face can provide relevant information by supporting either criminal or legitimate proposition (i.e., smothering or night's sleep scenario).