November 09, 2017
STRmix™, the sophisticated forensic software used to resolve mixed DNA profiles previously thought to be too complex to interpret, has been approved for use by four more U.S. agencies.
The Florida Department of Law Enforcement, Kansas City Police Crime Laboratory, Las Vegas Metropolitan Police Department, and Union County (NJ) Prosecutor’s Office Forensic Laboratory join 29 other U.S. labs which now routinely use STRmix™ in resolving DNA profiles. This includes everything from federal agencies such as the Bureau of Alcohol, Tobacco, Firearms, and Explosives (ATF) to state and local agencies such as the Michigan State Police, Texas Department of Public Safety, and the California Department of Justice.
STRmix™, which is celebrating its fifth anniversary of use in live casework, is also in various stages of installation, validation, and training in 51 other U.S. labs. Fourteen laboratories in Australia, England, Scotland, Republic of Ireland, Canada, and New Zealand are now using STRmix™.
“In five short years, STRmix™ has moved from being an experimental technology to the broadly accepted norm in cases in which a sophisticated forensic software is required to resolve mixed DNA profiles,” says John Buckleton DSc, FRSNZ, Forensic Scientist at the New Zealand Institute of Environmental Science and Research (ESR).
Buckleton, who developed STRmix™ in collaboration with ESR’s Jo-Anne Bright and Duncan Taylor from Forensic Science South Australia (FSSA), notes that STRmix™ has been successfully used “in numerous U.S. court cases and thousands of cases internationally, while there have been at least 13 successful admissibility hearings in the U.S. for STRmix™.”
Earlier this year, the Federal Bureau of Investigation (FBI) published its validation of STRmix™ for use on mixtures of up to five persons. Noting that STRmix™ offers numerous advantages over historical methods of DNA profile analysis and has greater statistical power for estimating evidentiary weight – all of which can be used reliably in human identification testing – the FBI began using STRmix™ in its casework in December 2015.
ESR recently launched an upgraded version of STRmix™ after a full year of technical development and testing. STRmix™ v2.5 contains a number of new features designed to improve functionality, speed, memory, and ease of use, including: multi-kit functionality, enabling interpretation of DNA profiles from different test kits; a likelihood ratio (LR) batcher tool, allowing users to calculate multiple LRs from multiple reference inputs to a previously run deconvolution; and a combined DNA Index System (CODIS) report.