The evidentiary values of “cold hits” in a DNA database search on two-person mixture

We provide a unified overview on the evaluation of the evidentiary values of cold-hit DNA matches between profiles in a DNA database and a mixed crime sample. Also discussed are methods of handling missing data in evaluating the DNA evidence. Through the analysis of a constructed murder case using Swedish data, we illustrate the applicability of the methods on various situations including the presence of multiple matches and consideration of allele drop-out. We also demonstrate the calculation of the probability of erroneous attribution as a measure of the effectiveness of the database search on DNA mixtures.