Could well be.He might not be a person who says a lot and might be remaining tight-lipped, making out he doesn't know anything. It will probably be up to the lawyer and team to present a theory of how the DNA matches.
Talking about DNA I've read the notes about the trial, but there hasn't been mention of the familial DNA, unlike the articles after the arrest where a familial DNA was mentioned. If a family member voluntarily gave their DNA could that matter be something which has been supressed?