The use of Bayesian principles in the reporting of forensic findings has been a matter of interest for some years.
Recently, also the GSR community is gradually exploring the advantages of this method, or rather approach, for writing
Since last year, our GSR group is adapting reporting procedures to the use of Bayesian principles. The police and
magistrates find the reports more directly accessible and useful in their part of the criminal investigation. In the lab we
find that, through applying the Bayesian principles, unnecessary analyses can be eliminated and thus time can be freed
on the instruments.
Like many forensic science labs, the Belgian National Institute of Forensic Science (NICC) is involved in a Quality
Assurance program aiming towards an ISO17025 Accreditation.
Since last year, a project is underway in the GSR lab to validate the method used in the analysis of GSR samples
acquired from the hands of suspects by SEM/EDX. The project is well underway, and is planned to lead to accreditation
for this technique by the start of 2010.
The presentation will discuss several aspects of the functioning of the lab that have to be addressed when preparing for
this accreditation. Some of these issues and problems are so involved that separate sub-projects were defined in order to
provide a manageable solution. The following topics will be treated in detail: definition of the scope of the accreditation,
the validation of the SEM/EDX method with respect to : accuracy, precision, reproducibility and robustness, and the
documentation of the Chain of Custody (CoC) of the samples and their storage. One specific sub-project that will be
discussed is the study of contamination monitoring in different relevant locations of the lab. Finally, as we have recently
acquired a new microscope, the technical criteria we used in the acquisition study will be presented with a focus on their
relevance in a QA context.
We feel this discussion is informative, both for labs that are pursuing a formal accreditation in the future, and those that
work already in such a context and are in the process of acquiring new equipment.