Evidentiary discrepancies in sexual assault casework within the US

Abstract

In recent years, a significant number of investigations have discovered up to 200 000 unsubmitted sexual assault kits (SAKs) in the US. While the public outcry was largely directed towards DNA analysis, the SAKs also contained biological specimens specifically designated for toxicological analysis. Due to the sensitivity of analytes in potential drug facilitated sexual assaults, the preservation and maintenance of the specimens is crucial in providing accurate toxicological measurements. The investigations into the unsubmitted SAKs have identified subjective law enforcement officer (LEO) rationale for the unsubmitted kits, however the impact on toxicological specimens has not been examined. This brief review of policies and guidelines with respect to forensic specimens has identified potential sources of evidentiary degradation, despite the use of chemical preservatives. With respect to temperature-controlled environments, the variation in SAK submission policies established throughout the US are potentially detrimental to the preservation of toxicological evidence. Degradation as a result of time-delayed collection and poorly maintained storage temperatures plays a crucial role for/in the interpretation of qualitative and quantitative toxicological results. This review finds these delays can be addressed through modernisation of facilities; electronic tracking of unsubmitted SAKs; mandated transfer of biological evidence within 72 h; and documentation of temperature within the chain of custody or other records. Without identifying the range of temperatures in which the evidence was exposed, forensic toxicologists may unintentionally provide erroneous interpretations of toxicological analyses – potentially casting doubt on the survivor’s recall of events and negatively impacting future sexual assault investigations.