You prosecute the one who seems most likely to have done it - who has a record, or was in the wrong place at the wrong time, or... Then you claim in court that

You prosecute the one who seems most likely to have done it - who has a record, or was in the wrong place at the wrong time, or... Then you claim in court that there was less than a 1 in a million chance that he matched the suspect's photo, omitting the fact that there were numerous other matches. This is already happening with some of the less accurate forms of DNA testing.