Institute Of Recherche Criminelle Of La Gendarmerie Nationale

Saint-Martin-de-Ré, France

Institute Of Recherche Criminelle Of La Gendarmerie Nationale

Saint-Martin-de-Ré, France
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Lecompte Y.,Institute Of Recherche Criminelle Of La Gendarmerie Nationale | Perrin M.,Institute Of Recherche Criminelle Of La Gendarmerie Nationale | Daude B.,Center Medical Interarmees Du Commandement Of La Gendarmerie Of La Reunion | Arpino P.,Chimie Paristech
Annales de Toxicologie Analytique | Year: 2012

Objectives: Methoxyisoflavone (5-methyl-7-methoxyisoflavone) is a dietary supplement employed by bodybuilders. Following a false positive result in a urinary cannabinoid screening test in the context of methoxyisoflavone use, this active ingredient and its metabolites are searched for in the urine sample to objectivize a possible cross-reactivity with the antibody screening test. An administration trial in healthy volunteers is also performed. Methods: After enzymatic hydrolysis, the urine sample is prepared by liquid-liquid extractions in acidic (pH 4) and basic (pH 9) conditions and then different analytical techniques are used: high-performance liquid chromatography-electrospray ionization-mass spectrometry (LC-ESI-MS) operating in positive ionization mode (sampling cone voltage 70 V) and gas chromatography coupled with mass spectrometry (GC/MS) after derivatization by acetylation and silylation. A reference solution of 5-methyl-7-methoxyisoflavone is analyzed under the same conditions. The administration trial was conducted in three healthy volunteers receiving orally 300 mg of methoxyisoflavone every 12 hours for 36 hours. A screening test and an analysis by LC/MS and GC/MS are performed on the urine emitted six hours after the last intake. Results: 5-methyl-7-methoxyisoflavone reference mass spectra were obtained in each set of analytical conditions. 5-methyl-7-methoxyisoflavone was not detected in the urine samples. Nevertheless, 5-methyl-7-hydroxyisoflavone, a metabolite of 5-methyl-7- methoxyisoflavone, was identified. After administration of methoxyisoflavone, all urine samples of the three subjects included in the trial resulted in a positive screening test for cannabinoids. 5-methyl- 7-hydroxyisoflavone was also detected in their samples. Conclusion: The analyses carried out and the administration trial with healthy volunteers confirmed the involvement of 5-methyl-7-hydroxyisoflavone, a metabolite of 5-methyl- 7-methoxyisoflavone, in a cross-reaction with a urinary cannabinoid screening test. © 2012 Société Française de Toxicologie Analytique.

Myskowiak J.-B.,Institute Of Recherche Criminelle Of La Gendarmerie Nationale | Saccardy C.,Brest University Hospital Center
Revue de Medecine Legale | Year: 2017

Diatoms are a reliable diagnostic tool for drowning. Yet, they are at the origin of controversies due to limits linked to the discovery site, discrepancies in the results induced by the methods used or non-conformities affecting the expression of the results. A survey of 26 forensic institutes (metropolitan France and DROM/COM) and 10 French laboratories was undertaken to get state of the art about drowning diagnostic techniques used from a sample of freshwater human corpses discovered in 2010 and 2011. The analysis highlights biases and limitations mainly related to methodological sampling rules, rate of decomposition of the corpse likely to cause hypothetic post mortem contamination of organs. Comparison of medico-legal data and laboratories results focus on representativeness of autopsy samples. In 2014, a "diatom" sampling kit was developed in the department 3F of the IRCGN. Single-use materials allow standardization of a sampling method at the discovery field and during autopsy. Between 2014 and 2016, the balance of diatoms activity at the IRCGN highlights an increase of analyses and a significant reduction of expertise delays. If the problem of water sampling is being resolved with the use of the kit, the main source of nonconformity always concerns the autopsy sample mass. A lower mass than normally required by the protocol is able to induce the rejection of analysis results. Standardization of a sampling method seems to be an effective solution to the problem of samples non-conformity. Furthermore, study of the "statistical weight" of an organ and blood diffusion phenomena will allow diatoms to give new light in case of suspicion of underlying pathology or sampling problem. © 2017 Elsevier Masson SAS.

Gaudry E.,Institute Of Recherche Criminelle Of La Gendarmerie Nationale | Dourel L.,Institute Of Recherche Criminelle Of La Gendarmerie Nationale
International Journal of Legal Medicine | Year: 2013

The Department of Forensic Entomology (Institut de Recherche Criminelle de la Gendarmerie Nationale, France) was accredited by the French Committee of Accreditation (Cofrac's Healthcare section) in October 2007 on the basis of NF EN ISO/CEI 17025 standard. It was the first accreditation in this specific field of forensic sciences in France and in Europe. The present paper introduces the accreditation process in forensic entomology (FE) through the experience of the Department of Forensic Entomology. Based upon the identification of necrophagous insects and the study of their biology, FE must, as any other expertise work in forensic sciences, demonstrate integrity and good working practice to satisfy both the courts and the scientific community. FE does not, strictly speaking, follow an analytical method. This could explain why, to make up for a lack of appropriate quality reference, a specific documentation was drafted and written by the staff of the Department of Forensic Entomology in order to define working methods complying with quality standards (testing methods). A quality assurance system is laborious to set up and maintain and can be perceived as complex, time-consuming and never-ending. However, a survey performed in 2011 revealed that the accreditation process in the frame of expertise work has led to new well-defined working habits, based on an effort at transparency. It also requires constant questioning and a proactive approach, both profitable for customers (magistrates, investigators) and analysts (forensic entomologists). © 2013 Springer-Verlag Berlin Heidelberg.

Baechler S.,University of Lausanne | Terrasse V.,Institute Of Recherche Criminelle Of La Gendarmerie Nationale | Pujol J.-P.,Institute Of Recherche Criminelle Of La Gendarmerie Nationale | Fritz T.,Institute Of Recherche Criminelle Of La Gendarmerie Nationale | And 2 more authors.
Forensic Science International | Year: 2013

False identity documents constitute a potential powerful source of forensic intelligence because they are essential elements of transnational crime and provide cover for organized crime. In previous work, a systematic profiling method using false documents' visual features has been built within a forensic intelligence model. In the current study, the comparison process and metrics lying at the heart of this profiling method are described and evaluated. This evaluation takes advantage of 347 false identity documents of four different types seized in two countries whose sources were known to be common or different (following police investigations and dismantling of counterfeit factories). Intra-source and inter-sources variations were evaluated through the computation of more than 7500 similarity scores. The profiling method could thus be validated and its performance assessed using two complementary approaches to measuring type I and type II error rates: a binary classification and the computation of likelihood ratios. Very low error rates were measured across the four document types, demonstrating the validity and robustness of the method to link documents to a common source or to differentiate them. These results pave the way for an operational implementation of a systematic profiling process integrated in a developed forensic intelligence model. © 2013 Elsevier Ireland Ltd.

Dourel L.,Institute Of Recherche Criminelle Of La Gendarmerie Nationale | Pasquerault T.,Institute Of Recherche Criminelle Of La Gendarmerie Nationale | Gaudry E.,Institute Of Recherche Criminelle Of La Gendarmerie Nationale | Vincent B.,Institute Of Recherche Criminelle Of La Gendarmerie Nationale
Psyche | Year: 2010

The forensic entomologist uses weather station data as part of the calculation when estimating the postmortem interval (PMI). To reduce the potential inaccuracies of this method caused by the distance between the crime scene and the meteorological station, temperature correlation data from the site of the corpse may be used. This experiment simulated the impact of retrospective weather data correction using linear regression between seven stations and sites in three climatic exposure groups during three different seasons as part of the accumulated degree days calculation for three necrophagous species (Diptera: Calliphoridae). No consistent benefit in the use of correlation or the original data from the meteorological stations was observed. In nine cases out of 12, the data from the weather station network limited the risk of a deviation from reality. The forensic entomologist should be cautious when using this correlation model. © 2010 Laurent Dourel et al.

Brutin D.,Aix - Marseille University | Sobac B.,Aix - Marseille University | Nicloux C.,Institute Of Recherche Criminelle Of La Gendarmerie Nationale
Journal of Heat Transfer | Year: 2012

We fully characterize the natural evaporation of human drops of blood from substrates and substrate-dependent behavior. The heat flux adsorbed by the drops for evaporation is measured by means of a heat flux meter. A side-view measurement enables access to the drop contact angle, wetting diameter, and initial height. A top-view camera allows for the monitoring of the drying regime (deposition, gelation, and fracturation). This directly measured heat flux is related to the evaporative mass flux obtained from the mass of the drop, and the two show good agreement. Both types of measurements indicate that regardless of the substrate type, there is first a linearly decreasing regime of evaporation when the drop is mostly liquid and a second regime characterized by a sharp decrease. We show that the evaporation dynamics are influenced by the substrate's wettability but not by the substrate's thermal diffusivity. The different regimes of evaporation exhibited by glass and metallic substrates are explained in terms of evaporation fluxes at the drop surface. In the case of wetting drops (below 40 deg), the evaporation flux is very important along the drop periphery and decreases across the interface, whereas in the case of nonwetting drops (about 90 deg), the evaporation flux is almost uniform across the droplet's surface. We show that these different evaporation fluxes strongly influence the drying behavior. In the case of metallic substrates, this enables the formation of a uniform "glassy skin" around the droplet surface and, in the case of glass substrates, the formation a skin along the drop periphery with an inward gelation front. This behavior is analyzed in terms of the competition between the drying time and the gel formation time. Unstable drop surfaces were observed at high initial contact angles and are very similar to those of polymer drops. © 2012 American Society of Mechanical Engineers.

Pham-Hoai E.,Institute Of Recherche Criminelle Of La Gendarmerie Nationale | Crispino F.,University of Quebec at Trois - Rivieres | Hampikian G.,Boise State University
Journal of Forensic Sciences | Year: 2014

We describe how a very simple application of familial searching resolved a decade-old, high-profile rape/murder in France. This was the first use of familial searching in a criminal case using the French STR DNA database, which contains approximately 1,800,000 profiles. When an unknown forensic profile (18 loci) was searched against the French arrestee/offender database using CODIS configured for a low stringency search, a single low stringency match was identified. This profile was attributed to the father of the man suspected to be the source of the semen recovered from the murder victim Elodie Kulik. The identification was confirmed using Y-chromosome DNA from the putative father, an STR profile from the mother, and finally a tissue sample from the exhumed body of the man who left the semen. Because of this identification, the investigators are now pursuing possible co-conspirators. © 2014 American Academy of Forensic Sciences.

Forensic science takes ever more important place in the investigation of crime. From the scene of crime to the Court, scientific stakes are multiple. Many participants are brought into the investigation: technicians, scientists, forensic pathologists, investigators and judges. Tensions are evident between them and the place of science within the judicial process is unclear. The main reason of this situation arises because physical evidence is poorly considered in the criminal investigation and not clearly established. The training of jurists and investigators does not cater for the supervision of scientific investigation. The role and the place of the scientists must be re-examined. The resolution of the tensions could go through the implementation of a new role, the scientific coordinator. This would consist of a paradigmatic change and a new complex scientific activity. This scientist would be associated to the investigator and to the judge to advise them throughout the judicial process from the scene of crime to the court. This coordinator should be.

Lecompte Y.,Institute Of Recherche Criminelle Of La Gendarmerie Nationale | Perrin M.,Institute Of Recherche Criminelle Of La Gendarmerie Nationale | Salle S.,Institute Of Recherche Criminelle Of La Gendarmerie Nationale | Roussel O.,Institute Of Recherche Criminelle Of La Gendarmerie Nationale
Journal of Analytical Toxicology | Year: 2012

The guidelines for screening of urinary cannabinoids require that all specimens testing positive should be confirmed by gas chromatography- mass spectrometry at a confirmatory test cutoff value of 15 ng/mL of 11-nor-9-carboxy-Δ9-tetrahydrocannabinol (THCCOOH). To assess the impact of lowering the confirmatory test cutoff value on the diagnostic sensitivity and efficiency of a cannabinoid testing program, the results of 986 confirmation analyses of positive screening tests, conducted in the framework of medical fitness examinations prior to enlistment in the French Gendarmerie between January 1, 2005, and December 31, 2009, were retrospectively studied. If the confirmatory test cutoff value of THCCOOH is set at 5 ng/mL instead of 15 ng/mL as recommended by guidelines, the number of confirmed results increases by 25.2%. The positive predictive value of the initial screening test rises from 63.9 to 80.0%. Only one true-positive applicant has appealed. His THCCOOH urinary concentration, which was incompatible with passive cannabis smoke exposure, was confirmed by another laboratory. The use of a confirmatory test cutoff value lower than that recommended significantly increases the diagnostic sensitivity of the screening program for urinary cannabinoids without altering its specificity. © The Author [2012]. Published by Oxford University Press. All rights reserved.

PubMed | ESPCI ParisTech, Institute Of Recherche Criminelle Of La Gendarmerie Nationale and CNRS Chemistry, Biology and Innovation Laboratory
Type: | Journal: Journal of forensic sciences | Year: 2017

Developing a strategy to characterize the odor prints of individuals should be relevant to support identification obtained using dogs in courts of justice. This article proposes an overview of the techniques used for the forensic profiling of human odor. After reviewing the origin of human odor-both genetic and physiological-the different analytical steps from sample collection to statistical data processing are presented. The first challenge is the collection of odor, whether by direct sampling with polymer patches, cotton gauze, etc., or indirect sampling with devices like Scent Transfer Unit. Then, analytical techniques are presented. Analyses are commonly performed with gas chromatography coupled with mass spectrometry. As they yield large amounts of data, advanced statistical tools are needed to provide efficient and reliable data processing, which is essential to give more probative value to information.

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