In most National DNA databases (NDNADB), only single source DNA profiles, and sometimes two-person DNA mixtures, can be searched provided a minimum number of loci (or alleles) is available. DNA profiles that do not meet these criteria (about 14 % of the traces analyzed in Western Switzerland) can be compared locally with candidates upon request from police services, used for one-off search, or remain unused. With the advent of probabilistic genotyping (PG), such complex DNA profiles can be compared to those stored in NDNADB based on likelihood ratios (LRs). In this pilot study, traces of known contributors and casework DNA profiles were used to evaluate the performance of the DBLR™ "Search database" tool in conjunction with the Swiss NDNADB. First, 40 DNA mixtures (2-5 contributors) from 15 volunteers were prepared in the wet laboratory. They were deconvoluted with STRmix™ and compared to a database containing the DNA profiles of these 15 volunteers, along with 174,493 person DNA profiles from the Swiss NDNADB (ground-truth experiments). Using LR thresholds of 10