Intelligence Technology Helps Maximize Resources in Murder Investigation

Police in Warwickshire, England, used Watson® from Xanalys, to track down the killer of 15-year-old Naomi Smith, found dead on Aynsley Common, Nuneaton, England. It enabled police to prioritize suspects and from a potential list of 800, find a DNA match within the first 15 samples to be taken.

Watson was used to analyze data from the force’s major investigations database, HOLMES (Home Office Large Major Enquiry System), apply offender profiles, prioritize suspects and designate resources. This resulted not only in the conviction of Naomi’s killer, but in large savings in manpower and cost.

Naomi’s body was discovered by her father and her best friend under a children’s slide in a recreation ground near her home. They had gone out to search for her when she failed to return home from posting a letter. She had been viciously attacked; her throat had been cut and there were bite-marks on her body.

The offender profile was completed by a forensic psychologist who compiled a series of attributes that would point to potential suspects. He concluded that the killer would probably be male and living within half a mile of the murder scene. It was determined that he was likely to be aged between 15 and 29, and probably knew the victim by sight. The psychologist also anticipated he would be a regular visitor to the recreation ground, would have no steady girlfriend and was likely to be known to police in connection with crimes of a sexual or violent nature.

Warwickshire’s Intelligence Research Unit had already fixed on an area within a half-mile radius of the scene, and set out to identify every male aged between 15 and 25, together with anyone outside this radius who frequented the Aynsley Common area. House-to-house teams used special questionnaires to identify and cross-check between households. The information gathered was fed back into the Intelligence Unit and then entered into specially created categories in the HOLMES database. This data was then analyzed by Watson, with the offender profile in mind, aligning ‘scores’ for potential suspects: the higher the number of attributes matching the offender profile, the higher the suspect appeared on the police list.

Further matching attributes gathered during the investigation were added to Watson to develop a visual representation. As well as highlighting links and graphically displaying information, Watson also enabled police analysts to question the data and identify links otherwise unseen, thereby uncovering the information needed to find Naomi’s killer. Heading up the Intelligence Unit, Detective Sergeant Jez Grew said: “This is the best approach I’ve yet encountered, because everything was inclusive and nothing was exclusive. Traditionally, you might have had the same list of 17 attributes, selected one of those attributes as a start-point for the search and, as a result, passed over a culprit who had all the other attributes except the start-point attribute. Watson information is far more relevant to eliminating suspects according to all the co-ordinates set for the investigation.”

The real break in the case came when the Forensic Science Service successfully obtained a third-party DNA profile — a DNA trace that could be used to identify the killer – from the bite marks found on Naomi’s body. Police would have been faced with the task of obtaining DNA mouth-swab samples from some 800 young men. And at a significant cost per sample, plus the cost in resources, time and manpower required to collect the samples, the expense would have been prohibitive. However, using the Watson analysis results from the offender profile; police were able to determine which potential suspects they should test first, i.e. those with the highest number of matching attributes. The killer’s DNA was identified in the first 15 swabs to be taken.

Detective Superintendent Bayliss said: “Watson is unique in its capability to analyze bulk information — imported from HOLMES — in terms of relevant lines of enquiry. In this case, it eliminated those lines of enquiry using less manpower and in a shorter timescale than previously required. We have found no other software that achieves this so effectively. In short, Watson saved us time, money and resources.”