Subway Using DNA Spray to Catch Robbers...That Doesn't Wash Off.

Don’t rob Subway, because it will spray its DNA all over you…literally.

ABC 6 Knoxville reports that Subway has a new security system called “Intruder Spray System” that sits above the door and contains a vat of a synthetic DNA substance. Whenever there's a robbery, an employee presses a button, and the stuff sprays all over the guy as he leaves. Not sure what happens if the robbery happens after hours...

It's invisible to the naked eye, but it stays on your skin for up to seven weeks...you can't wash it off.

It'll show up under a black light so the cops can check a suspect for it and prove he either was or wasn't the person who robbed the Subway. Each store has its own unique DNA, just to make sure there aren't any false positives.

For now, Subways in Knoxville, Tennessee are getting this security system, but it's going to spread to thousands of them nationwide soon.

Photo By: Scott Olson/ Getty Images