The contribution of DNA databases for stored sexual crimes evidences in the central of Brazil.

Accumulation of sexual assault evidences unsubmitted to forensic DNA testing raises concern and it favors low rates of sexual crimes resolution. However, with the advent of DNA databases, these evidences have provided valuable information for investigations. In Brazil, the use of DNA databases is recent and few studies assessed their contribution to criminal resolution. In this regard, this study aimed to evaluate the potential of the DNA Database of Goias State, Central Brazil (BPG-SPTC/GO) in the resolution of sexual crimes without suspects through the insertion of profiles obtained from stored untested evidences collected between 2004 and 2018. Samples were submitted to DNA extraction by differential lysis, followed by the amplification of STR autosomal markers, capillary electrophoresis analysis in the ABI 3500 genetic analyzer and insertion in the BPG-SPTC/GO using CODIS 7 software. The rate of eligible samples for insertion and rates related to the obtained matches were evaluated. Statistical analyses were performed with Epi Info ™ v.7 and BioEstat 5.0 software. A total of 275 samples were submitted to DNA testing, 202 out of them (73.5%) presented eligible profiles for insertion. A total of 176 (64%; 176/202) were inserted, one crime scene profile from each case. Overall, 60 hits were generated, all series sexual matches; a higher prevalence of forensic hits was detected (81.7%; 49/60) and a total of 32 criminal investigations were assisted (18.2%; 32/176). As the use of DNA databases in Brazil is recent and Brazilian criminal law has stringent requirements, our results reinforce that the use of DNA databases for stored sexual crimes evidences is a feasible forensic tool and that the increasing of the number of both types of profiles in DNA databases, evidences and criminals, causes positive reflects on the number of matches generated. However, further studies are necessary to evaluate if this effectiveness reflects positively on conviction rates of sexual crimes.