We tested the knife for fingerprints, but there were none to be found. Luckily, we have some other evidence to fall back on.
First, we'll test the blood on the murder weapon using STR analysis. Perhaps the assailant had been cut in a struggle, and left some of his or her blood on the knife.
We'll test for three different STRs in the blood sample and look for a match with the victim or one of the suspects. We've taken blood samples from each of the suspects, and from Conwell, and done STR analysis on them. Only a perfect match will do - all the STR patterns have to match completely to get a positive identification.
