Impact case study database

Forensic science has always been a cornerstone of the criminal justice system. From highlighted evidence in the 2019 Science and Technology Select Committee report (Forensic science and the criminal justice system: a blueprint for change), the benefits of rapid forensic science are “ *the potential to reduce costly police investigative time through early identification of offenders or the exoneration of innocent suspects; earlier arrests can lead to a lower financial impact of prolific offenders who are otherwise free to re-offend; and of course compelling, high quality forensic science can lead to earlier guilty pleas, quicker trials and a resultant reduction in expensive court time.*” At the same time, the report warned of what could come from an underdeveloped capacity for – and leadership in – UK forensic science: “ Crimes may go unsolved and the number of miscarriages of justice may increase” [5.1a].

Representing a first for such an inquiry, the University of Warwick and West Midlands Police (WMP) submitted joint evidence to the same 2019 Select Committee report [5.1b] based on an ongoing and productive collaboration which started in 2014 at the forefront of police forensics [5.2]. Submission of this evidence led to a roundtable meeting in July 2019, facilitated by the Home Office and chaired by the Forensic Science Regulator (Dr Gillian Tully), where the new Forensic Centre for Digital Scanning and 3D Printing (founded in 2019 between Warwick and the WMP) was heralded as best practice – in particular for “ demonstrating the value that can be leveraged from University research to provide evidence for forensic investigations” [5.2]. With national reach, the Centre provides access to the forensic capabilities at Warwick to police forces across the UK and in overseas territories [5.3]. Stand-out examples of impact between Warwick and the WMP – on criminal cases, practitioner training, cost savings to police forces nationwide and on the development of forensic standard operating procedures (SOPs) – are detailed below:

Benefits of micro-Computerised Tomography (micro-CT) and 3D printing in forensics: As a complementary technique to existing post-mortem procedures, micro-CT grants a number of distinct advantages in criminal investigations. In addition, preparation of 3D printed models for use in the court room aids with prosecution of serious crimes. Just as production enhancements can result in efficiencies in manufacturing, so too can micro-CT and 3D printing constitute analogous process improvements in the criminal justice system:

• Forensic methodological advancements. In cases of strangulation, factures in the laryngeal skeleton were often too subtle to detect in conventional autopsy techniques. By scanning at a spatial resolution of 40μm, micro-CT allows for detailed examination of these delicate structures – with subsequent research [3.7] differentiating between accidental death and murder. This has been used directly to rule out foul play and well as in multiple convictions, with the former highlighted in the following section. On advancing national understanding the Assistant Director of Forensic Services at WMP expanded: “ This research is truly ground-breaking and has helped change our understanding of the impact of the use of force on the body during numerous modes of strangulation” [5.2].

• Non-invasive, non-destructive analysis. As with analogous Computerized Axial Tomography (CAT) scans, micro-CT similarly leaves forensic samples untouched. A Home Office registered Consultant Forensic Pathologist in the Forensic Pathology Services (FPS) outlined that this offers “ significant value to forensic analysis at the front end of an investigation” before complementary, destructive analysis (e.g. histology) is deployed [5.4]. Where samples themselves are delicate – a burnt shoulder bone [5.5] – the non-destructive nature of micro-CT allows for structural interrogation while leaving this crucial forensic evidence intact [5.3].

• Cost and time savings. Analysis has shown that in three separate criminal cases GBP10,000 was saved for each, with Mark Payne (Assistant Chief Constable of WMP) further qualifying that this saving extends to around a third of all investigations where micro-CT has been applied. By extrapolation, at least GBP500,000 had been saved up to mid-2020 – with Mark Payne adding, “ Technology and research at Warwick has therefore significantly improved our investigative processes and outcomes” [5.3]. Any savings and efficiencies gained in policing correspond directly to a saving for the taxpayer.

• Presentation of sensitive evidence. Using 3D printed artefacts as well as interactive presentations of micro-CT scans in court reduces the distress of both the jury and family members who are present [5.3], and otherwise assists in the jury’s understanding of a very complicated pathological picture [5.6]. This expert witness evidence has been used in a number of convictions, with key examples detailed below.

Micro-CT and 3D printing in criminal investigations: Between 2014 and 2020 micro-CT was used in 171 criminal cases in 18 police forces, in addition to facilitating multiple convictions and with Warwick forensic services remaining available during COVID-19 lockdown [5.3]. Overall, this prolific usage is a testament to the broad applicability of micro-CT in forensics and indicates extensive national uptake. Below are but a few notable investigations where Warwick technology made a vital contribution:

• In a case of complex dismemberment, Warwick researchers delivered one of the first examples of micro-CT technology as a forensic radiological method in a UK courtroom. Asked to examine a charred piece of evidence thought to contain human bone, researchers discovered it was a perfect jigsaw fit to another piece of bone found elsewhere, and were able to show the tool marks on both pieces in micro scale (20 microns). This provided a crucial link between the site where the body had been disposed of and the home of the murder suspect – leading in part to a murder conviction [5.5]. In recognition, Prof Williams was awarded a Chief Constable's Award for his work on Operation Sanderling: “ You worked closely with the investigation team with ground breaking 3D printing and scanning technology. Not only did this result in the crucial identification of a missing shoulder bone, but your subsequent assistance with the pathology and trial processes assisted the jury with their understanding of the case and eventual positive outcome” [5.7].

• Following the detection of several injuries to an 18-month-old infant, micro-CT scanning was conducted at WMG. The right femur (thigh bone) showed a grossly displaced fracture with a large amount of callus forming around it, indicating that healing processes had begun without proper medical attention and the ribcage displayed 20 individual fractures in different stages of healing. The [text removed for publication] of the Crown Prosecution Service indicated that this “ evidence was instrumental in establishing the circumstances and causation of injury and death.” Further, [text removed for publication] elaborated that this “ was distinctly advantageous both from an evidential review and prosecution presentation perspective”, as with no witnesses to the crime establishing the sequence of events leading to the death by alternative means is critical [5.6]. The trial resulted in a manslaughter conviction.

• Beyond securing convictions, research at Warwick has also been crucial in ruling out foul play in suspicious circumstances. In the post-mortem examination of an elderly male, skull fractures were revealed to be only a few centimetres apart, which is not consistent with a fall and so murder was impossible to initially rule out. In working with a forensic scientist, modelling by the University revealed that in this instance the deceased had fallen backwards and injured himself on a door latch [5.3]. Similarly, in a separate instance that drew on techniques linked to the published research [3.7], 3D scans of neck structures revealed a death to have been caused by accidental asphyxiation rather than strangulation as was initially suspected. On the subject of ruling out foul play, Assistant Chief Constable Mark Payne says: “ The ability to provide the families of the deceased with clarity earlier in the investigation has been invaluable and is one of the key benefits of the project” [5.3].

Wider uptake – CPD training and standard operating procedures (SOPs): Through the foundation of the Forensic Centre for Digital Scanning and 3D Printing in 2019 between Warwick and the WMP [G3], an ongoing and lasting practitioner impact has been felt by UK police forces and forensic science experts. The Centre was founded expressly to make Warwick technology available throughout the UK, enabling the innovation to be exploited and disseminated nationally [5.2]. The Centre goes hand-in-hand with training delivered by the University, with over 140 specialist practitioners receiving CPD on image processing methods and 3D visualisation techniques to uncover evidence in homicide investigations [5.3].

In addition, standard operating procedures (SOPs) for micro-CT have been developed by Warwick and WMP. These SOPs cover all aspects of forensic analysis of samples by micro-CT, including transportation, storage and calibration of the machines [5.2]. As a result, since 2016 referrals of suspicious child deaths and strangulation to Warwick for post-mortem examination have become national practice through use of these SOPs [5.4]. This establishes innovations from Warwick as an important part of the overall investigative arsenal available in UK policing.

In terms of broader engagement nationally a talk presented by Prof Williams and Assistant Chief Constable Mark Payne at the British Science Festival (BSF) was attended by 150 students from multiple schools, helping to further spark interest in UK forensic science. At the 2019 BSF talk Payne observed that through science “ it’s increasingly difficult to get away with murder” which, ultimately, is “ good news for everyone” [5.5].