A trial for attempted murder, currently scheduled for 3 May in Lafayette, Louisiana, may for the first time in the United States feature a new type of evidence: phylogenetic analysis, in which DNA samples from various sources are compared to see how closely related they are. In this case, a doctor is alleged to have tried to kill his former mistress by injecting her with HIV-infected blood from one of his patients, and the prosecution wants to use the analysis to support its case. The evidence was ruled admissible in a preliminary hearing, although the defense is now challenging that ruling.