When Danielle Moorcroft, a 21-year-old pregnant heroin addict, was found bludgeoned to death in June 2002 in Bolton, the police knew that finding her killer would not be easy. The nature of Moorcroft's work - she was a prostitute - meant that investigators would be dealing with a large pool of suspects and a mass of data for analysis.
Two decades earlier, solving Moorcroft's murder might have been impossible. But a key IT system used by UK police forces has made it easier to sift through volumes of information and quickly elicit the clues needed to push an investigation forward.
Central to the Moorcroft investigation was the use of the Home Office Large Major Enquiry System 2 (HOLMES 2), the second incarnation of a case-management system originally set up around the UK in the mid-1980s.
HOLMES 2, designed under contract by Unisys, is a repository for all case data. It has features that will link and graph-related items. As investigators collect documents, statements and evidence. That information is chronicled in HOLMES 2's Oracle databases.
Structured information, such as people's names and vehicles, is indexed, allowing for searches to show when those terms appear in other documents, said Helen Mylam, HOLMES 2 product manager. "Very easily you would be able to find out all the information you needed to about that particular person and decide what you wanted to do about it," Mylam said.
A subsystem from Autonomy for searching free text can also search unstructured data such as witness statements, prioritising their relevance using sophisticated algorithms, according to Unisys.
HOLMES 2 uses custom-built software and off-the-shelf components. The client-server architecture is based on workstations running Microsoft's Windows 2000 Professional or NT 4.0 and Unix servers running Sun Microsystems' Solaris or The SCO Group's Unixware. Each police jurisdiction has its own HOLMES 2 setup, but they can be linked over a nationwide police extranet for co-operative work on a case, Mylam said.
In the Moorcroft case, HOLMES 2 stored data on more than 7,000 people linked to the investigation, including their ages, previous convictions and other personal data, said Peter Jackson, acting detective chief inspector for the Greater Manchester Police. As investigators interviewed people, they would bring their notes to a trained HOLMES 2 user, who entered the data into the system.
Pieces of evidence are also described and logged, Jackson said. CCTV footage was described and put into HOLMES 2. From the information in the system, investigators can make decisions about who to interview next, and that interview would eventually come back to the incident room for entry into HOLMES 2.
Specific queries are then made of the system based on names, ages and descriptions. The system can find common traits in the information, potentially raising the profile of those that police may want to focus on.
In the Moorcroft case, police ended up with a large number of people they wanted to interview, Jackson said. But certain clues allowed police to narrow the field. The assailant left behind an asthma inhaler, and a DNA profile suggested that the assailant was likely to be of Asian ethnicity. The police conducted a mass DNA screening of men in the area.
In HOLMES 2, investigators were able to set up a category that isolated people who used inhalers. They then set up a subcategory for inhaler users who were Asian, between the ages of 17 and 30 and who obtained their inhaler from a pharmacy within a mile radius of the murder scene, Jackson said. HOLMES 2 generated a priority group of people who should be interviewed.
"The advantage of HOLMES is when you are dealing with masses of information, masses of people, it helps you to process all these people and administrate it," Jackson said. "And then, nothing is missed."
After the interviews and the DNA mass screening, however, none of the suspects identified appeared to be the murderer. "We thought perhaps if all our logic was right, it must be some kind of human error on the way that had caused us to miss it," Jackson said.
Police found later that about 60 people who received asthma inhalers had not been entered into HOLMES 2 due to a discrepancy outside the police department in how patient prescription records are stored. Those people were interviewed and sampled and one was a match: Stuart Milsted, a 30-year-old university graduate, who later confessed to police that he had hit Moorcroft repeatedly with a brick.
Milsted was sentenced to life in prison in October 2005. He was the 6,782nd person to be linked to the investigation in the database, Jackson said.
"So you can imagine if you dealt with that kind of inquiry using any kind of paper system, with all the vehicles and the telephones and the CCTV logs ... it would be a nightmare to process," Jackson said.