Thieves and robbers in London use a special type of invisible liquid called smartwater. This spray was helping robbers in London but now its Police’s turn. Police have found that this spray is visible with Ultraviolet light. Ultraviolet light makes the spray visible in the form of green hue.
According to London police, one suspect thief was caught after checking his face and clothes with ultraviolet light. Thief was found guilty of stealing from car, he was sentenced to 46 hours of community service and was also fined $650.
Smartwater is impossible to washout of clothes and can also stay on the skin for week. While on the other hand London police is checking suspicious person with ultraviolet light, this action of London police has led to a 40% drop in street robbery and 80% drop in burglary. For more checkout this video.
Green Faced Robbers Are Now Afraid Of London Police Trap