If the comparison had shown 55% concordance would he have been guilty or innocent?
You question makes no sense. None of your posts do, but this one makes even less sense than usual. If you compare a particular sequence of OJ's DNA to a corresponding sequence of unknown sample DNA, and you only get a 55% correspondence, that's a pretty clear indicator that your unknown sample is from a non-human species.
motA, ExbB, and MTH1022 are all similar, with correspondences in the 30-50% range, but they're not identical because they come from different organisms, representing different genera and species. And the whole idea behind exploring the similarities is to explore how closely related different organisms are to each other. Once again, you've discovered that things that are different are not identical to each other. Congratulations.