The contribution of forensic science to crime analysis and investigation: forensic intelligence

The debate in forensic science concentrates on issues such as standardisation, accreditation and de-contextualisation, in a legal and economical context, in order to ensure the scientific objectivity and efficiency that must guide the process of collecting, analysing, interpreting and reporting forensic evidence. At the same time, it is recognised that forensic case data is still poorly integrated into the investigation and the crime analysis process, despite evidence of its great potential in various situations and studies. A change of attitude is needed in order to accept an extended role for forensic science that goes beyond the production of evidence for the court. To stimulate and guide this development, a long-term intensive modelling activity of the investigative and crime analysis process that crosses the boundaries of different disciplines has been initiated. A framework that fully integrates forensic case data shows through examples the capital accumulated that may be put to use systematically.     

“She Thinks She's Like a Man”: Marriage and (De)Constructing Gender Identity in Colonial Buha,Western Tanzania, 1943–1960

La nouvelle orientation de la politique économique au Sénégal vise à accroître les revenus des pauvres et à attaquer la pauvreté là où elle est principalement localisée. La stratégie de réduction de la pauvreté va être mise en oeuvre dans un contexte de libéralisation des échanges commerciaux internationaux notamment dans le secteur agricole. Dans ce contexte, nous avons développé un modèle d’équilibre général calculable micro-simulé multi-ménages permettant d’évaluer l’impact que pourront avoir ces politiques agricoles à l’échelle des ménages, et nous avons établi le lien entre ces réformes économiques, la pauvreté et la distribution de revenu. Ce modèle offre beaucoup de flexibilité en permettant notamment de modifier la distribution des groupes cibles qui ne méritent pas d’être retenus avant l’exercice de simulation afin d’effectuer l’analyse de pauvreté et d’inégalité ex post à l‘exercice de modélisation. Nous avons également comparé les effets, en terme d’analyse de pauvreté et d’inégalité, entre une distribution paramétrique et une distribution empirique, et montré que ce choix engendrait des différences significatives quant aux effets sur la pauvreté. Les impacts sur la pauvreté sont assez importants, ce qui montre que cette approche offre un outil riche permettant d’évaluer l’impact de politiques économiques ou chocs externes sur la pauvreté et la distribution de revenu. De plus, nos résultats d’analyse de pauvreté suite à une augmentation du prix des biens agricoles sont contraires à d’autres applications à différents pays sur le même thème.     

Sugar and fatty acid analysis in ecstasy tablets

Sugars and stearates (composed of fatty acids) are both frequent components used in the production of ecstasy tablets. Their analysis can therefore provide supplementary information useful for drug intelligence. Links established using these substances would be very significant as they should give us information about the manufacturer of the tablets. Two methods have been developed for the analysis of sugars and fatty acids by GC-MS and were applied to 109 ecstasy tablets. Characterisation of the samples should allow the differentiation of a certain number of them and furthermore their classification into groups. This is obtained by analysing the raw data using chemometric methods. Several pre-treatments have been tested together with six similarity measures on a small number of ecstasy samples in order to determine which combination would best characterise one ecstasy sample and differentiate it from the others at the same time. Normalisation followed by the fourth square and applied together with the squared cosine function appeared to give the best results and has been applied to all samples. The correlation values obtained of each sample with all others express the probability of a presence of a link between two samples. In order to verify the signification of these values, and thus of a link, all samples have been compared considering the data visually according to three selected criterions. The 109 examined samples could be divided into 67 groups, with 43 of them containing only one sample. Considering the distribution of their correlation values, sample pairs showing a value below 0.23 can be considered as linked. As the excipients are necessarily related to the blending, which also includes the active substance, and variation in the excipient content has been proven by the grouping of the samples, a low similarity value does indicate a link with regard to the producer. In conclusion, it appears that the result obtained with the excipients is certainly very valuable, but all other available information has to be taken into account as well before making any conclusions.     

Use of gold nanoparticles as molecular intermediates for the detection of fingermarks

Among the numerous methods dedicated to the detection of latent fingermarks, the MultiMetal Deposition (MMD) offers, as a main advantage, the ability to be applied on a great number of porous and non-porous surfaces, e.g., paper, plastic, glass, latex, and polystyrene, even if wetted. While considered as a powerful and sensitive technique, MMD is often neglected, mainly because of operational limitations (siliconized vessels, restrictive pH domain, numerous immersion baths, ...). In this contribution, we propose a modification of the standard MMD method so that the procedure is simplified with a number of baths reduced to a minimum. To reach this goal, it was necessary to obtain a fully operable solution which could detect fingermarks in a single step. We chose to take advantage of the molecular recognition mechanisms by functionalizing the gold nanoparticles with a molecular host able to bind itself to gold while keeping the ability to trap molecules in solution. Cyclodextrins were chosen as they can be easily chemically modified to offer gold-binding abilities. Moreover, they are widely used as hosts for various molecular guests (dyes, luminescent molecules, ...). This new formulation has been tested on three different surfaces to attest the feasibility of this strategy. Successful results were obtained with detailed fingermarks offering a good contrast to allow their identification without the need to enhance the results (such as with a physical developer). If the new formulation behaves very similarly to the old one, in terms of experimental conditions, it offers the additional advantage to develop fingermarks after immersing them in only one bath. The goal is thus reached.     

Technical note: latent fingermarks, colloidal gold and multimetal deposition (MMD). Optimisation of the method

Operational details and optimisation of the colloidal gold or multimetal deposition technique (MMD) for the detection of latent fingermarks on non porous and porous surfaces demonstrate the power of the method. Control of particulate size, pH, reagent, handling are shown to be essential. A difficult case example illustrates the potential of MMD.