Actually, I've never really understood the reason behind this. Surely, it doesn't really matter WHY you suspected somebody in the first place. If there's enoug

Actually, I've never really understood the reason behind this. Surely, it doesn't really matter WHY you suspected somebody in the first place. If there's enough other evidence to show irrefutably that they committed the crime, there shouldn't be a huge difference between the first tip coming from some random guy phoning the cops and saying "there's a dodgy looking guy here" or getting a random match from a DNA database? I can see the intent behind probable cause for e.g. traffic stops, because that is designed to stop prejudiced-based harassment. But if there is an extremely close DNA-match found randomly, that search hasn't caused any harm to anyone, and should be a perfectly good reason to investigate someone a little more thoroughly. Maybe it should be disclosed in the case, e.g. "we became suspicious because of the DNA matching, and further investigation showed the victim's blood all over his house, clothes, and the murder weapon that he'd put back in his tool rack" should be a slam dunk conviction not grounds for letting someone go on a technicality because e.g. there wasn't a nosy neighbour who'd reported them for being too noisy or whatever.