Bank robbers have been wary of the exploding money pack that covers them with a bright colored dye for years.
But now they've got one more thing to worry about as a more sophisticated way of marking robbers is making its way into stores and businesses that are frequently targeted by thieves, a device that sprays an invisible DNA mist on the bad guys that won't wash off for weeks.
The mist, which is now being used in nine countries and coming to the U.S. soon, shows up under ultraviolent light and contains a DNA code that police stations scan for when they bring in criminals. The unique code irrefutably links criminals to the scene of the crime.
"The word DNA spreads fear into even the most hardened criminals," said Jason Brown, business director of Selectamark, the company that created SelectaDNA Spray.
Selectamark says the spray stops crime by scaring criminals away with warning signs posted outside of protected buildings that read "You Steal, You're Marked."
The mist is so fine, it's unlikely a robber would know he's been hit. It sinks into the target's skin and hair where it sits for weeks.
"You can take a shower three times a day, but the DNA stays on," said Jean-Paul Fafie, the manager at one of several McDonald's restaurants in Rotterdam, the Netherlands, that had the spray system installed.
Fafie is a big fan of the system for good reason. He was robbed at gunpoint five years ago while closing up the store at 5 a.m. Three men burst in, and shoved a gun to his head while they tied him up and stole about 8,000 euros, or $11,000.
"It feels safer," he said of having the system, which was installed about a year ago and so far hasn't had to be tested. "We hope that the robbers think twice before they come in."
No arrests have yet been made that are attributed to the DNA mist, and police say while the mist is extremely effective at protecting individual shops the overall rate of crime isn't down. It's just changed locations.
"They go now to stores without DNA spray. It's not that they do less criminal activity," said Quirine Schillings, a communications officer for the Rotterdam police. She added that in Rotterdam, robberies are way down and none of the locations with the spray installed have been burglarized. But crime has risen in poorer areas outside of town that don't have the resources to install the system.
The SelectaDNA Spray has potential for helping police solve who-dun-it mysteries.
"Often times it's not that they [police] don't know who they [robbers] are, it's that they don't have evidence to get a prosecution," said Selectamark's Managing Director Andrew Knight. SelectaDNA Spray helps that problem, and has the potential to put more guilty parties behind bars, he said.
But Schilling points out that the spray alone isn't enough evidence to convict someone. It proves the culprit was there, but not that they actually committed a crime. Police have to rely on other evidence, like surveillance cameras, to prove what took place.
The spray, which was developed in 2008, is being used in a series of European countries from Belgium to Hungary. The Bank of New Zealand has just invested in the product and will have all of its branches installed with the spray by next month, Knight said.
He said SelectaDNA Spray may soon be coming to the U.S., but officials declined to comment other than noting big-name retailers and banks are interested.