IRMS based evidence passes the test

At the two latest FIRMS (The Forensic Isotope Ratio Mass Spectrometry Network Ltd) conferences, presentations were made describing the status of IRMS based evidence in criminal proceedings [S. Doyle, T. Chau and J. Howa, IRMS based evidence passes the 'test' (aided by FIRMS) - an important milestone, in: 8th FIRMS Conference, 2022; J. Ehleringer, J. Howa and T. Chau, Stable isotope evidence in the U.S. courts, in: 7th FIRMS Conference, 2019]. One of those cases was of particular significance in that it established the admissibility of IRMS (isotope ratio mass spectrometry) based expert testimony having satisfied the US Federal Rule of Evidence (FRE)702 'Testimony by Expert Witnesses' in the State of Colorado. While specific to the State of Colorado and the particulars of the case, the admissibility of IRMS based evidence in other cases might be supported by such a ruling. This paper provides the detail of the process by which IRMS based evidence was found to be admissible and in so doing also provides practical guidance on how to satisfy FRE 702 and meet a Daubert challenge. It also highlights the role of approval by the FIRMS Network of both practitioners and their methods in support of admissibility [The FIRMS Network Ltd., FIRMS Approved Practitioners, [Online]. Available: https://www.forensic-isotopes.org/fafp.html [Accessed 11 May 2023].].