From "Law and Order" to "CSI," not to mention real life, investigators have used fingerprints as the gold standard for linking criminals to a crime. But if a perpetrator leaves prints from different fingers in two different crime scenes, these scenes are very difficult to link, and the trace can go cold.
There has been no science to back up fingerprints being unique enough to determine identity by. I’m not sure “going to find out” is quite the same as “has never been proven to be true.”