This is a gangbuster story from the Marshall Fund. Your DNA travels. Grab a pole in the subway and the next person may pick up the DNA. He/she murders another, your DNA may end up on the victim’s body, but you were never there.

“In 1997, when Australian forensic scientist Roland van Oorschot stunned the criminal justice world with a nine-paragraph paper titled “DNA Fingerprints from Fingerprints.” It revealed that DNA could be detected not just from bodily fluids but from traces left by a touch. Investigators across the globe began scouring crime scenes for anything—a doorknob, a countertop, a knife handle—that a perpetrator may have tainted with incriminating “touch” DNA. But van Oorschot’s paper also contained a vital observation: Some people’s DNA appeared on things that they had never touched.”

https://www.themarshallproject.org/2018/04/19/framed-for-murder-by-his-own-dna