So much promise, so little delivery: Underuse of biological evidence collected from sexual assault victims treated in an Italian specialised hospital centre

In an Italian hospital centre treating victims of sexual assault, requests for genetic testing of biological samples collected during forensic medical examinations (GT cases) were identified from 2003 to 2023, and details of the results of body fluid identification (BFI) and DNA analysis were obtained from the designated laboratories. Elements that could influence the decision to perform forensic DNA analysis were derived from the medical records of GT cases and a comparison group of patients whose samples were not genetically tested. The overall proportion of GT cases was 7.8 %, remaining limited even after the implementation of the National DNA Database (BDN-DNA) in 2017 (14.3 % in 2023). Items that were significantly more common in GT cases compared to the comparison group included: a positive sperm microscopy result; short time since intercourse (TSI) (<24 h in >80 % of GT cases); reported ejaculation; aggression by a stranger; group violence; absence of injuries. Male DNA profiles were obtained from 52.1 % of samples using a direct-to-DNA approach, and from 39.2 % using a traditional strategy involving differential extraction, depending on the preliminary BFI results. The success rate was significantly higher for shorter TSI and positive BFI test for semen, although male DNA profiles could be obtained in 18–27 % of semen negative samples. Only 25.0 % of eligible DNA profiles obtained after 2017 were uploaded to BDN-DNA. The results show the underuse of biological evidence in the investigation of sexual violence cases in the Italian criminal justice system and the lack of awareness of the potential of BDN-DNA.