Forensic marking helps link criminals to their crime

Jan 30, 2012, 8:55 GMT

Sydney - The signs are going up outside Australia's petrol stations, pubs and clubs warning would-be robbers that a hi-tech sentinel is on duty.

Inside the door, up there in that beige box, is wizardry that could provide incontrovertible evidence linking them to the hold-up they might be contemplating.

The signs alert the baddies to a forensic marking system in which a spray can propel a fine mist of water-borne synthetic DNA over a retreating robber. The unique DNA tracer stays on the skin for up to six weeks - it cannot be washed off - and is easily seen under ultraviolet light.

If the robber is caught in the act, or apprehended later, the tell-tale marker is almost certain to be there.

'The criminal is forensically linking themselves to the crime scene at the time the crime was occurring and that's critically important,' said Tania Jolley, managing director of Adelaide-based DNA Security Solutions. 'To find DNA in a public venue isn't incriminating but it is incriminating that they were present at the time of the crime.'

Jolley's company is bringing to Australia a technology that has caught on in Europe. 'We developed a system that was for the Australian marketplace,' she said. 'Ours is the only system in the world that has the capacity to spray up to 15 times.'

The spray is more than 99-per-cent water, non-toxic and gets on skin and clothes probably without the knowledge of the intruder. The spray is activated by a panic button concealed below the counter, by a motion sensor or by a hand-held transponder.

'It's very rare that you'd have a complete covering (of clothes),' Jolley said. 'Even with a balaclava, you'd have an area of skin. And it also marks the things they steal. If they have a gun, it marks the gun.'

As with security cameras, the warning of a forensic marking system is usually enough to put criminals off.

'In Adelaide we're achieving greater than a 95-per-cent deterrent rate,' she said. 'We have businesses here who were victims of very serious armed robberies by very nasty gangs - they were experiencing four in a year - and they've now been over two years without an incident.'

The technology is most advanced in Britain, where companies are now offering systems that coat steel formwork and other expensive metal structures with synthetic DNA that rubs off on the hands of robbers.

For the systems to work well, police need to be cooperative. They are in Britain, but in Australia there is debate over the admissibility of forensic marking evidence - and whether the private sector is encroaching on police work. 'We work with the police who work with criminals and in that way they are educating them on our behalf,' Jolley said. 'That gives a very high deterrent effect.'

Criminals may not fully understand forensic marking but they are likely to avoid premises where they might learn more about it.