Abstract: The invention provides methods for interrogating mixtures of nucleic acids through amplification of short tandem repeat markers (loci) within each nucleic acid, and thereby analysis of the amounts of each allele amplified from each marker, and in particular interrogating mixtures of DNA, such as forensic (trace) samples, to identify the most probable number of contributors of nucleic acid in the mixture, the most probable ratio/proportion of the nucleic acids in the mixture, and thereby the most probable nucleic acid sequence for each marker within a nucleic acid.