A method of analysing DNA samples from mixed sources includes i) obtaining an observed result relating to a value set for a characteristic of the DNA; ii) randomly selecting a selected value set for that DNA characteristic and generating an expected result from that selected value set; iii) comparing the observed result and the expected result and quantifying the difference there between. The method also includes iv) considering the selected value set to be the optimal match; v) randomly selecting a different selected value set and generating another expected result from that selected value set; vi) comparing the observed result with the another expected result and quantifying the difference there between; vii) replacing the existing optimal value set with the different selected value set of step v) if a criteria is met. The method further includes viii) repeating steps v), vi) and vii) at least 10 times; ix) the last optimal match being taken to be the optimal match for the value set for the DNA.