 The aptness of the analogy has been challenged (Donnelly and Friedman 1999). Searching a larger database no doubt increases the probability of finding a match at some point. But the relevant proposition here is not  “At least one of the profiles in the database would randomly match the crime sample”. Rather, the relevant proposition is “The profile of the defendant on trial would randomly match the crime sample”. The probability of finding a match between the defendant and the crime sample does not increase because other people in the database are tested. In fact, suppose everyone in the world is recorded in the database. A unique cold-hit match would be extremely strong evidence of guilt since everybody would be excluded as a suspect except one matching individual. Instead, if the random match probability were multiplied by the size of the database, the probative value of the match should be quite low. This is counter-intuitive.