Nowadays the use of DNA profiles in forensic identification problems is a very common procedure. The observance of a mixture trace resulting of a crime that has been committed is a very interesting and challenging phenomenon for the laboratories and for the judicial systems. The hypotheses that can be considered and compared in cases of mixture traces are discussed in this work. In court two hypotheses, the prosecution hypothesis and the defence hypothesis, lead the dispute in the case presented. The use of Bayesian networks in the analysis of DNA mixture traces is a powerful tool in complex cases. That allows an easy evaluation of the likelihoods for the whole hypotheses suggested by each case.