The distributions of the number of included profiles in a two-person mixture based on autosomal STRs for four panels. The four panels were the 13 CODIS core loci, the 19 autosomal loci in section A, the 10 most informative of the 13 CODIS core loci (D18S51, FGA, D21S11, D8S1179, VWA, D7S820, D3S1358, TH01, D13S317, and D16S539), and the 10 least informative of the 13 CODIS core loci (D8S1179, VWA, D7S820, D3S1358, TH01, D13S317, D16S539, CSF1PO, D5S818, and TPOX). The distributions were obtained by simulation, in which 1 million profiles were first generated as a database, and then 1 million two-person mixtures were randomly generated without replacement. Each mixture was searched against the database to determine the number of candidate part-contributors beyond those that comprised the mixture. The Y-axis represents the proportion of mixtures with specific number of candidate contributors in a database search. For example, with 13 CODIS loci, no candidate contributors were identified for 67.7% of mixtures. Only 1.3% or 0.4% of two-person mixtures generated more than 10 or 20 candidate contributors, respectively. With the 19 loci in section A, almost 100% of two-person mixtures had no candidate contributors in a database of 1 million profiles.