 Consider now a more complex two-stain scenario. Suppose a crime was committed by two people, who left two stains at the crime scene: one on a pillow and another on a sheet. John Smith, who was arrested for a different reason, genetically matches the DNA on the pillow, but not the one on the sheet. Meester and Sjerps (2004) argue that there are three plausible pairs of hypotheses associated with numerically different likelihood ratios (see their paper for details). The three options are listed in  table 2,  where \(R\) is the random match probability of Smith’s genetic profile and \(\delta\) the prior probability that Smith was one of the crime scene donors.