The terrifying world about DNA is the fact that you can be tracked down across time. But of course, that's also the interesting part of it too. This tale, is perhaps one of the greatest DNA identification ever made and it's all from a kiss on a woman's hand.
One woman driving down a road in Germany saw a man by the side of the road, and she pulled over wanting to help him but all he wanted was directions to a nearby town. When he pulled out a map and spread it over the car, he used that distraction as a way to reach into her purse and pulled out her wallet. Before she left, he kissed her hand to thank her, leaving her without any money.
When she did find out that her wallet was missing and pieced things together, she didn't have enough to identify him. But she remembered the hand kiss which was sloppier than just a peck - the usual kind anyone would give. The police used his saliva and DNA to eventually identify him.
They didn't find him immediately though, but it took three years later, when he was across the border in Austria, briefly arrested for fraud and has his identifying details recorded. He managed to flee custody, so he's still out on the lam. But case in point - he was identified.