CaseSolver: An investigative open source expert system based on EuroForMix.

Affiliation

Department of Forensic Sciences, Oslo University Hospital, Oslo, Norway. Electronic address: [Email]

Abstract

For very serious crimes, reporting scientists often have to contend with complex cases where literally hundreds of items are submitted by investigators for analysis. In order to efficiently expedite the challenge of comparing reference profiles to evidence profiles, many of which are mixtures, we have developed an investigative open source expert system CaseSolver. We have analysed a real case based on GlobalFiler involving 119 evidence profiles and 3 reference profiles. To provide a demonstration of the power of the system we also added the three references to a fictive large database of 1 million individuals in order to test subsequent recovery of the presumed true contributors. CaseSolver was used on a Fusion 6C validation study involving 25 two- to four-person mixture profiles based on 14 reference profiles. The sequential use of simple allele comparison, the qualitative model (forensim) and the quantitative model (EuroForMix) makes the analysis very fast and accurate - and finally, the software generates a list of potential match candidates which can be exported as a report. From these two studies we found that the resolution of match candidates from CaseSolver was the same as that reported by a scientist who worked manually through the samples, except that CaseSolver highlighted two manual errors. For the validation study we found low template DNA samples giving negative results, which demonstrate the limitations of the tool; but overall our assessment shows that CaseSolver will benefit all analyses involving mixture interpretation and screening. Importantly, CaseSolver removes the very time-consuming aspect of manual comparison and gives improved quality by preventing manual errors.

Keywords

DNA comparison,Database searching,Expert system,Likelihood ratio,