In the frame

An advanced photo identity system is just one of the innovations being developed to provide police with a battery of hi-tech forensic equipment to fight drug and terrorist-related crime. Jon Excell reports.

The year is 2020. It is 3am and a dingy London backstreet is the scene of a grisly murder. Apart from one shocked and inebriated witness, the streets are empty. Yet within minutes, alerted by long-range surveillance cameras that have spotted the activity through the darkness, police arrive on the scene. It is the sort of random crime that was once thought unsolvable but now, armed with an array of hand-held devices that will do in minutes what once took weeks in a lab, police are soon hot on the trail. Gone are the days of the educated hunch and the magnifying glass: today in the UK a host of detection, imaging, and analysis devices are being developed that promise to make this hi-tech forensic vision a reality soon. Much of this development is driven by the EPSRC’s crime prevention and detection technologies programme. A modestly-funded initiative – it has received £14m since its launch in 2002 – the programme has nevertheless become a model example of how academia and end-user organisations can establish a fruitful dialogue. According to Dr Alasdair Rose, the amiable Scot who heads the project, the success of the programme boils down to healthy, collaborative partnerships. ‘All the projects must be in collaboration with a user organisation – whether it’s the Home Office, the forensic science lab or a company. We don’t want to support innovative approaches that users or other organisations can’t take on board because they’re impractical and there’s a responsibility on the part of the researchers to think within a kind of deployment framework. There is also a responsibility on the part of the users to think outside the box and be willing to accept new ideas.’ Rose is realistic about the time it takes to nurture these ideas from development to deployment. Crime technology takes a notoriously long time to complete this journey, with a seemingly endless number of bureaucratic and technical hurdles to clear before it finds its way into the hands of the police. Even then, it could be years before a discernible impact on crime statistics is made. However, given this caveat, the EPSRC programme is already beginning to bear fruit. One of the most notable success stories is an advanced photo identity system under development by Kent company VisionMetric. Dr Chris Solomon, the physicist who heads the Kent University spin-out, explained that while conventional ID techniques ask witnesses to visualise and describe the face of a criminal, his approach is more in tune with the way that people actually remember faces. The system, known as EigenFit, asks witnesses to look at a range of randomly generated images of faces. Those that bear even a slight resemblance are fed back into the system and blended by a computer to create a new set of faces that reflect their choices. The idea is that eventually the image will evolve to closely resemble the suspect. The group has recently added an automatic ageing tool to the system, so that if a witness thinks a face looks familiar but a bit younger or older than the suspect, the age of the face can be instantly adjusted. The technique, which could eventually be used at a crime scene while a suspect’s face is still fresh in a witnesses’ memory, will shortly begin Home Office trials with the Derbyshire and Leicestershire police forces, said Solomon. It has been favourably received following informal trials with Kent police, he added. A key aspect of Solomon’s EigenFit project has been the involvement of psychologists to evaluate the responses of users. In the early stages of the project he worked with a group from the Open University and the system is now being evaluated by a researchers from Goldsmiths College, London. According to Alasdair Rose, this ability to tap into apparently unrelated areas of expertise has characterised many of the crime programme’s biggest successes. A similar cross-fertilisation of ideas is under way at Cambridge University where a team of astronomers is applying its star-gazing expertise to the development of long-range surveillance cameras. Dr David MacKay, who heads the group, said computational techniques used by astronomers to counter the image distortion caused by atmospheric conditions could also be used for ground-based photography. MacKay’s so-called ‘lucky-imaging’ method was inspired by the way the human brain works. He said: ‘If you go out on a hot day and look towards the horizon you see the heat haze and things shimmering through it. If you take a snap of that with your camera it’s going to be all fuzzy but if you keep staring at it there are moments when you can see quite clearly. This is because if you keep staring, your mind is building up a picture of what’s there beyond the turbulence.’ His computational technique is essentially doing the same thing, he said. ‘We are taking high-speed images, breaking the images into sub-cells and within each cell looking for the sharpest moments. Once we’ve identified the sharpest picture from each cell we put them all back together again and make a picture.’ The group is experimenting with equipment based on a CCD chip provided by UK sensing specialist e2v Technologies but the challenges of adapting the technique to ground-based photography are acute. ‘The difficulty with ground-to-ground surveillance is that the problems are 10 times worse than in astronomy,’ claimed MacKay. ‘The turbulence is going on a timescale that is 10 times shorter and so we really have to run cameras that are 10 times faster. The difficulty is that if you take pictures at several hundred frames per second, even on a bright, sunny day, there’s no light and we want a technique that’s going to be useful in poorly illuminated conditions.’ The group is developing plans for a prototype system that addresses these kinds of problems through, for instance, the use of infrared lighting. Alasdair Rose suggested that, once refined, the technique will potentially be attractive to Revenue & Customs, which could use the system to detect offshore smuggling operations. In a separate development, just as the photofit system is receiving a revamp courtesy of Solomon’s team, so fingerprint dusting – staple of many a 19th century crime novel – is moving into the 21st century. A group of Swansea University engineers is collaborating with the Forensic Science Service and Qinetiq on the development of a system able to recover fingerprints from gun cartridges or even fragments of exploded bomb. The high temperatures of an explosion frequently destroy many of the traces that conventional dusting powder detects, so obtaining fingerprint samples from such material has traditionally been extremely difficult. However, the Swansea group has been using a scanning Kelvin microprobe, which measures differences in electrical potential across a surface, to detect the electrochemical changes caused by sweat from a fingerprint. These changes are measured and used to build up a picture of the print. According to the group the technique works on curved surfaces as well as samples that have been exposed to temperatures as high as 600oC. It has also been successfully tested on iron, steel, aluminium, zinc and brass. While academics suggest a world of hi-tech crime-fighting is just around the corner, their claims must be measured by those that will be using the technology. One of the people at the sharp end of this relationship is Sean Doyle, team leader of the forensic science lab within the Defence Science and Technology Laboratory. Funded by the Home Office, Doyle’s job is to spot emerging technologies for his main customer, the police. He is encouraged by what he sees. ‘The facetious comment is that what we all want is a tri-corder [the hand-held analyse-everything device featured on Star Trek] but there is a definite trend of bringing the lab to the scene,’ he said One extremely promising technology that will enable this, claimed Doyle, is the progress being made in the development of lab-on-a-chip microfluidic systems for the detection of explosives. Such systems could, in theory, enable police to carry out complicated forensic analysis at the scene of a crime. Doyle’s group is working with Prof Peter Fielden at Manchester University on the development of such a system for the rapid detection of inorganic explosives such as ammonium nitrate. According to Doyle, a portable device that will allow officers to perform analyses at the scene, thus eliminating the delays while samples are returned to the laboratory, will begin trials next spring with the Met’s anti-terrorist branch. Hand-held devices could also be useful to the police in other areas of work. A number of UK groups are developing portable detection systems that could be used to detect drugs and explosives before they cause damage. One encouraging area is the work being done on devices that exploit the properties of THz waves, which lie between infrared and microwaves in the electromagnetic spectrum. These are of particular interest for security applications because many substances such as explosives or pharmaceuticals have characteristic fingerprint spectra in the THz frequency region. Also, while harmless to humans, they can penetrate clothes and packaging materials and be used for the imaging of concealed items. One such system receiving EPSRC funding is under development at St Andrews University in Scotland. This compact device, designed specifically to identify drugs concealed in clothes bags and envelopes, could also be used to detect hazardous chemical or biological agents. The group, headed by Prof Malcolm Dunn, is testing a prototype device with a variety of chemicals provided by analysis service the Forensic Alliance. For Doyle, the Holy Grail of forensics research is a technique known as Isotope Ratio Mass Spectroscopy (IRMS), a methodology that has long been used by geochemists and scientists to find out the composition of a physical sample. ‘We’re putting a lot of money into developing this for forensic purposes, to the extent that on a few occasions it has actually been used to provide evidence to go into court,’ he said. The beauty of IRMS he said, is that it has the potential to figure out a material’s exact provenance. ‘It tells you where things came from and has potentially a very high discriminatory power. The idea is to be able say that a batch of explosives found on a particular person has the same origin and history as a bulk explosive found somewhere else – that’s a different type of evidence that a chemist would normally generate and put into court,’ he said. Doyle predicted that as well as helping anti-terror investigations, IRMS will also have a huge impact on the war against drugs, with the police using it to make the link between drugs found in a club and a ‘Mr Big’. Doyle is certain that the technique will one day play a huge role in forensics, but said it is at least five years away from field deployment. The reason for this is that in order to be effective it would have to be deployed on a global scale. ‘Unless it can be used as something that can be applied to volume crime it won’t be able to realise its full potential,’ he said. ‘It’s similar to DNA in the sense that it will only have its full impact if you create very large international databases of explosives, so that when you run an explosive you can interrogate a database and find out immediately where this explosive might have originated from and what raw materials might have been used to make it.’ The first tentative steps towards such a vision are being made in the UK, through the FIRMS network of researchers. Another initiative established with EPSRC money, this is laying the building blocks for the big, searchable databases that an effective IRMS system would require. ‘I think it will be big, but like any area of industry there are people who are wedded to what they do at the moment and have some interest in the status quo. It’s starting to get there and governments are putting money into it – there are signs that its slowly gathering momentum,’ said Doyle. There is plenty of technology for the UK’s law enforcers to get excited about, and with so much in the pipeline it is tempting to contemplate a future in which the chances of getting caught are so high that villains will decide that crime doesn’t pay. The sobering likelihood, however, is that as the police become increasingly sophisticated, so will their quarry.