In the name of privacy, I personally wouldnt give up my sample and I dont think anyone should be forced to give up their sample, unless they commit a felony and are sent to jail.
I’m glad they solved this cold case and hopefully they will solve more. However, it is obvious they used other innocent person’s data without their content. It would definitely piss me off knowing someone used my personal information for other purpose then it was meant. Afterall this business is based on trust. Fortunately, I don’t share such information as my DNA, but who knows whether they don’t already have it in their database. They can have yours or anyone as well. I would have to be naive thinking they do everything by the book.