People don't seem to realize how valuable and many times private DNA information really is otherwise a large number of them would have resisted this dragnet.
Am I the only one thinking this kind of large scale collection of DNA information should no be allowed without some very powerful circumstantial evidence.
Not just you happen to live in the same city a person was murdered in.
http://en.wikipedia.org/wiki/Colin_Pitchfork
Particulary interesting to me is the fact that the initial mass screening did not find the perpetrator, because he had paid somebody to give a sample for him. But he was eventually caught because the stand-in couldn't (or didn't want to) keep a secret.
Wikipedia mentions no controversy, although of course that doesn't mean there wasn't one.
I wouldn't mind submitting a DNA sample if it helps the police find a murderer. Maybe it was some distant cousin of mine, and my DNA will help them narrow their search.
Unlikely? It's very likely. We interact with tons of people each day. Also consider cases were the DNA is from a person close to the victim, but who isn't the murderer. Perhaps a friend came by the house and then left, and another came in and did the murder. Or a person sleeps with someone (perhaps an one-night-stand) and then is murdered, say by a jealous partner. The DNA could be from an interaction previous to the murder.
And of course, if the police is "sure" they have the suspect (like they often are, especially is he's say black or poor or something like that), they would also consider it "OK" to plant some DNA obtained for him to be "discovered" in the murder scene. Police has been found (in court) pulling such shit with falsified evidence) for decades.