The case of Robert Young, accused of the murder of a rival gang member, is a prime example of a case in which forensic geosciences and the use of scanning electron microscopy were instrumental in ensuring a conviction.
On 8th May 2003, gang leader and known drug dealer James Herbert Johnston was shot dead at his home in Crawfordsburn, Northern Ireland. Being a member of the Red Hand Commando, a loyalist paramilitary group, Johnston had inevitably acquired a number of enemies over the years.
The incident was called in by Johnston’s neighbours, who heard shouting following by a series of gunshots at about 10:35 that evening, and witnessed two men running away from the scene through a yard and towards fields. The victim had been shot 11 times by two different firearms, a .45 ACP pistol and a 9mm pistol, and he was pronounced dead at the scene.
Robert Young, aged 41, was soon arrested under suspicion of murdering Johnston, along with an accomplice.
It was believed that the two assailants had fled the scene, taking an escape route which passed through a number of fields and yards. This escape route, filled with thick gorse bushes, barbed wire fences and various waste materials, soon proved to be ripe with forensic evidence. Upon being examined by a doctor, Young was found to have acquired numerous abrasions “consistent with scrambling through rough terrain and through thick and sharp vegetation”, though Young claimed they were acquired during a fight.
An extensive examination of the surrounding area was conducted, led by a police dog who soon followed the trail of the suspects. Various pieces of forensic evidence of note were collected, including blood found on a barbed wire fence along the escape route which was later found to be consistent with Young’s blood. A number of discarded gloves and balaclavas were recovered, though insufficient DNA evidence was retrieved from these to link them to the perpetrators. Footprints and fresh tyre marks were discovered in the field near the scene, of which plaster casts were taken for later examination.
But amongst the most interesting evidence presented was that of geological origin.
During the investigation, police seized a blue Ford Fiesta car, belonging to the defendant’s brother but frequently used by Young, which was subsequently examined. On the car mat in the footwell, a white-coloured substance was recovered which required specialist identification.
Dr Ruffell, a geology lecturer from Queen’s University Belfast was called upon to provide his expertise in the examination of soils, sediments and various organic materials found at the crime scene and surrounding area. A sample of plasterboard found in the yard through which the suspects had fled was collected due to its similarity to the material found in the car. Another specialist called upon for assistance, Dr Pirrie of the University of Exeter, aimed to find a way of comparing the material found in the car to the material found in the yard, using a number of plasterboard samples acquired from a local hardware shop as references. The samples were subjected to analysis by scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM-EDX) with an automated system known as QEMSCAN. This technique allows for both the microscopic examination of the physical features of a sample, as well as providing elemental identification.
Using this technique, Pirrie identified a number of minerals present in the samples and established their abundance and co-occurrence. The material in the car was found to be a plaster product (gypsum-based), as the expert had initially suspected. Through analysis of the different samples, including the car sample, the yard sample and those acquired from the hardware shop, Pirrie could identify subtle variations in the mineralogy and make-up of the samples, allowing him to distinguish between different sources. Pirrie ultimately concluded that the sample from the car floor mat was comparable with that from the yard and yet different from the plasterboards acquired at the store. Based on the mineralogical signature of the samples, he suggested that the occupant of the car had either been present in the yard used as an escape route, or else they had been in another location which just happened to contain that same plasterboard.
During the trial, the defence called in their own geological expert, Dr Hodgkinson. Having examined the QEMSCAN data acquired by Pirrie and accepting this as good data, she disagreed with some of the interpretation of the information and highlighted some of the issues of automated systems such as QEMSCAN. Hodgkinson declared that although there were obvious mineralogical similarities between the plasterboard samples acquired from the car and the yard, there were also certain differences that should not be ignored. The expert witness testimony provided by the two geologists highlighted the possibility of individual experts interpreting data in a different way, ultimately reaching unalike conclusions that could be the difference between the defendant being found guilty or innocent.
Despite the defence team’s use of their own expert, based on Pirrie’s geological analysis and other pieces of evidence linking the defendant to the offence, Robert Young was found guilty of murder.
R V Robert John Benson Young, Lorraine Young and Susan Ferguson