[jlamberts]

Bayesian statistics says the opposite. By looking at the history of an entire city, you're giving yourself a highly uninformative prior. This means that it's very difficult to actually draw conclusions from the results. You have to reduce your population size first, and then perform your "test" (looking at search history) on the subset of the population who actually has a reasonable chance of committing the crime even without the search evidence.

[rayiner]

It depends on how probative the specific evidence is. If you had a database of everyone's DNA, and wanted to figure out whose blood was on the murder weapon. Your prior is highly uninformative, but the DNA evidence is so highly probative that the resulting identification is probably quite reliable.