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Should Rape Kit Testing Be Prioritized by Victim-Offender Relationship? Empirical Comparison of Forensic Testing Outcomes for Stranger and Non-stranger Sexual Assaults

NCJ Number
Criminology & Public Policy Volume: 15 Issue: 2 Dated: May 2016 Pages: 555-583
Date Published
May 2016
29 pages
This study examined the DNA forensic testing outcomes from 894 previously untested sexual assault kits (SAKs) from Detroit, Michigan, with a focus on how many of these SAKs would produce DNA profiles eligible for upload into CODIS (Combined DNA Index System), the national forensic DNA database maintained by the Federal Bureau of Investigation, and then how many would produce CODIS hits (DNA matches) to other crimes.
Fifty-four percent of the SAKs associated with stranger-perpetrated sexual assaults yielded CODIS-eligible DNA profiles, producing 156 CODIS hits (DNA matches) and 51 hits matched prior sexual assault offenses in CODIS (i.e., serial sexual assault hit). Forty percent of the SAKs from non-stranger rapes had CODIS-eligible profiles, producing 103 CODIS hits and 18 serial sexual assault hits. CODIS entry rates and CODIS hit rates were equivalent between stranger and non-stranger SAKs; serial sexual assault hit rates were significantly higher for stranger SAKs. These results highlight the importance of testing both stranger and nonstranger SAKs, as they have an equivalent likelihood of producing CODIS hits. The findings do not support policy recommendations that stranger-perpetrated SAKs should have testing priority over non-stranger SAKs. Prioritizing stranger SAKs may have unintended negative consequences on the utility of CODIS by limiting the number and type of eligible DNA profiles that are referenced in the federal DNA database. (Publisher abstract modified)

Date Published: May 1, 2016