Volatile organic compounds: instrumental and canine detections link an individual to the crime scene

Egyptian Journal of Forensic Sciences

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[1] 0000 0001 2168 2547, grid.411489.1, Department of Legal, Historical, Economic and Social Sciences, University of Catanzaro, Catanzaro, Italy;0000 0001 2176 9482, grid.4462.4, Department of Anatomy, University of Malta, MSD 2080, Msida, Malta;0000 0001 2200 8888, grid.9841.4, Department of Experimental Medicine, Section of Human Physiology and Unit of Dietetics and Sports Medicine, Università degli Studi della Campania “Luigi Vanvitelli”, Naples, Italy;0000 0004 1757 1969, grid.8158.4, Department of Biomedical and Biotechnology Sciences, Section of Human Anatomy and Histology, University of Catania, Catania, Sicily, Italy;0000 0004 1757 1969, grid.8158.4, Section of Legal Medicine, “F. Ingrassia” Department, University of Catania, Catania, Italy;0000 0004 1757 1969, grid.8158.4, Section of Legal Medicine, “F. Ingrassia” Department, University of Catania, Catania, Italy;0000 0004 1757 1969, grid.8158.4, Department of Medical and Surgical Sciences and Advanced Technologies GF Ingrassia, University of Catania, Via S. Sofia 78, 95123, Catania, Italy;0000000121049995, grid.10796.39, Department of Clinical and Experimental Medicine, Section of Legal Medicine, University of Foggia, Foggia, Italy;0000000121049995, grid.10796.39, Department of Clinical and Experimental Medicine, Section of Legal Medicine, University of Foggia, Foggia, Italy;0000 0001 2168 2547, grid.411489.1, Department of Legal Medicine, University of Magna Graecia di Catanzaro, Catanzaro, Italy;Forensic Toxicology Sections, “G. Tatarella” Hospital, Cerignola, Foggia, Italy;

关键词: Forensic science;    Volatile organic compounds;    Human scent;    Gas chromatography/mass spectrometry;    Dog training;    DNA analysis;   

DOI  :  10.1186/s41935-019-0139-1

来源: publisher

【 摘 要 】

BackgroundWhenever a crime is committed, forensic personnel are requested to collect every kind of evidence to establish the relationship between the suspects and the crime. When any evidence is accidentally destroyed or not found, there is one type of latent evidence that is always deposited at the crime scene: unique human scent. Recently, the use of trained canines to detect selective human scent at a crime scene has increased. To consolidate this kind of evidence, it is essential to have an exact knowledge and an awareness of the chemical signature of the volatile compounds that could indicate the presence of the alleged offender at the crime scene.This experimental study aims to detect the volatile organic compounds (VOCs) released from subjects who handled scent-articles to imprint their odor on. After handling, each scent-article was wrapped in sterile and VOC-free cotton gauzes for 48 h for secondary transfer. VOCs were detected by headspace/solid-phase microextraction-gas chromatography/mass spectrometry (HS/SPME-GC/MS) and well-trained dogs, at different time points (up to 15 days). Furthermore, the possibility of further DNA detection after contact was also investigated to propose a novel approach able to identify a subject from this latent forensic trace.ResultsData show that inter-individual human scent composition includes different VOCs, but dogs were able to discriminate the individual who touched the object at the crime scene. The dog training procedure showed excellent sensitivity (between 99.48 and 100%) and specificity (between 60 and 100%), having a positive predictive value (PPV) ranging between 97.94 and 100% and a negative predictive value (NPV) ranging between 85.71 and 100%. Preliminary work on DNA analysis released after contact yielded positive results, even if further studies are necessary, expanding the same experimentation to a larger sample with the aim of obtaining a statistically significant result.ConclusionData show that human scent is a good source of VOCs and a good target for canine training. The well-trained dog represents a specialized biological device able to discriminate personal human odor from any contaminants in the mixture detected by instrumental analysis. Furthermore, this study proposes the use of human scent as a forensic latent trace for DNA profiling.

【 授权许可】

CC BY