It is matching, it's just not matching with as much certainty as they would like. Matching DNA from an unknown person to a known person does not yield a yes/no answer; it yields a probability. If they would expect the markers that they were able to measure to be present in 1 out of every 9000 people, that is still pretty remarkable. Think about how few 9000 people there are in the US. It isn't like they said 1 out of every 2 people have these markers.