Security company claims to catch criminals by spraying them with human DNAS

In the Netherlands, store owners are trying a weird new tactic to stop thieves. As criminals leave the scene, they're sprayed with an invisible mist full of human DNA. How, exactly, does this prevent crime?

The New York Times reports:

The mist - visible only under ultraviolet light - carries DNA markers particular to the location, enabling the police to match the burglar with the place burgled. Now, a sign on the front door of the McDonald's prominently warns potential thieves of the spray's presence: "You Steal, You're Marked."

The police acknowledge that they have yet to make an arrest based on the DNA mist, which was developed in Britain by two brothers, one a policeman and the other a chemist. But they credit its presence - and signs posted prominently warning of its use - for what they call a precipitous decline in crime rates (though they could not provide actual figures to back that up).

Security company claims to catch criminals by spraying them with human DNAS

The mist, along with a wide range of improbable DNA-related security products, are sold by a company called SelectaDNA.

According to the SelectaDNA website:

Our warning signs, posters and labels, telling criminals to stay away, are hugely effective because of the "DNA Fear Factor". Our DNA evidence frightens the life out of criminals and provides the evidential chain Officers require to be more effective in their jobs.

The company sells its scary signs for between 8-10 Euro, and a container of SelectaDNA "grease" can cost over 500 Euro. Prices on sprayers of the sort installed in the McDonalds are "as quoted." They also sell a range of "microscopes" and pseudoscientific "DNA coding kits" for up to 100 Euro.

Security company claims to catch criminals by spraying them with human DNAS

I wish this were a hoax, but sadly it's just another example of snake oil sales in the genomics age. Supposedly the reason the DNA is necessary - as opposed to the UV-sensitive mist - is that each store can mix up its own bunch of unique human DNA to tag thieves with. So now when the police catch criminals, they can sequence the DNA sprayed on their skin to see whether they've stolen cash from McDonalds or from the hash cafe where this whole "security scheme" probably originated in the first place.

There is a certain enjoyment to be had imagining the security infrastructure that would be required to catch the sprayed criminals. Ultraviolet light checkpoints? But then how will we tell the criminals from all the ravers who thought it would be hilarious to coat themselves in the DNA spray because it helps them glow "naturally"?