This paper is based partially on the experiences of the author as an expert in forensic genetics and partially on experiences gained
during her visit to Forensic Science Service laboratories in Trident Court, Birmingham and the London Metropolitan Police
Laboratory in June 2008. The author’s discussions and exchanges of experiences inclined her to present some issues relating to the
cooperation of the Police and public prosecutors with forensic experts in England and Wales. Forensic Science Service has
constructed a framework for routine cooperation between Police and forensic experts called Case Assessment and Interpretation
(CAI). A fundamental new factor proposed by the CAI in the approach to examining material evidences from the scene of the
crime is a precise estimation of the value of the information that it is possible to obtain from preliminary analysis of evidences
even before beginning laboratory analysis. In other words, the aim of CAI is to help the fact finder to make the right decision. This
enables rational use of financial resources for expensive analyses (e.g. genetic ones) and rational use of forensic expert time, and
may significantly reduce the time of case report preparation, which is very long in Poland nowadays.

Evidential value of evidence; DNA; Likelihood ratio; Bayesian networks