SmartWater shows up under ultra-violet light
A North Wales Police station is the latest to install technology to allow burglary and theft suspects to be scanned for incriminating evidence.
St Asaph station, which covers Denbighshire and Conwy, now has UV lighting to detect any traces of a chemical called SmartWater.
The force has seen more businesses and schools using a spray device with the water to protect their property.
The scheme has also been successfully used in other UK police forces.
SmartWater has already been used in the area to "postcode" moveable property.
Where it is installed in buildings, it will spray over anyone who breaks in and leave them covered in colourless water which can be detected under UV light.
St Asaph's community safety officer Sgt Johnny Hill said: "The beauty of the product is that SmartWater contains a unique forensic code which enables us, through forensic testing, to distinguish the exact location where the individual has broken into.
"Spray pattern analysis can also identify whether the individual was caught under the spray or had it transferred unknowingly on to them at the scene or near the crime scene."
"Washing or dry cleaning clothes will not remove SmartWater and only a sample the size of a pinhead is needed to establish where the individual was sprayed.
"The product is already widely used to postcode property and this development will be a further help to us in crime detection - it really is an excellent tool."
"More and more businesses, schools and cash in transit vehicles are using the spray - many in conjunction with their alarm systems.
"As Smartwater it is such an effective tool we're hoping than many would-be thieves and burglars will think twice before committing a crime."
Anybody arrested on suspicion of committing an offence brought in to the St Asaph station will be tested for the substance.
Among Welsh forces, Dyfed-Powys Police use the technology in their Powys division at Newtown, while Gwent Police have a detection suite in Ystrad Mynach.
South Wales Police handed out SmartWater kits to residents of Cathays in Cardiff last year to mark household items in a bid to cut burglaries in the area.
It also installed detection lighting at city centre police stations and local pawnbroker shops.