I think @techmom99 is right that it is possible this could cause a glitch in his case, or at least be a cause for appeal after they convict him on it (which they almost surely will). Does it constitute some kind of illegal search or privacy violation for them to have used the relative’s DNA for the initial match? Personally, if I have a relative who is a rapist or murdered, I’m down with the police finding them through my DNA. Obviously my relative would see it differently… But I could see how challenges to this might wind up in the Supreme Court at some point, whether from this case or some other similar one.