WMG Skull
A 3D print of a skull segment with hammer and spanner imprints.
WINNER of the TCT Inspex Award 2019. Submit your design-to-manufacturing innovation for this year’s TCT Awards here.
The Criminal Justice System is steeped in traditions of enforcement, accountability, rehabilitation and righteousness. It is conformist, cautious, conservative in its ways, which over centuries only change gradually. And with good reason, because there are livelihoods and reputations at stake within the four walls of a courtroom that can see a jury of 12 and a single judge dictate the rest of the defendant’s life.
Beyond any reasonable doubt, the prosecution must prove the defendant carried out what is alleged, the jury must decide whether they are guilty or not, and as the gavel falls, the judge must order their punishment or their reprieve.
Through time, new methods of pleading their respective cases have evolved. In this regard, DNA profiling has perhaps been the biggest breakthrough. It was developed in 1984 by Sir Alec Jeffreys, by 1986 was introduced in sexual assault and murder trials, and before long was standard practice.
“Does anyone question DNA anymore? It will be the same for 3D printing,” teases Professor Mark Williams, at the University of Warwick’s Centre for imaging, Metrology and Additive Technology (CiMAT) inside Warwick Manufacturing Group (WMG).
In 2014, WMG received a phone call from West Midlands Police. On either end of the phone were Williams, leader of CiMAT, and Detective Inspector Harry Harrison, who, working a case, had a favour to ask. He needed to demonstrate the severity of the accused’s actions with minute precision and absolute clarity.
What followed would provide the case study for the group’s January 2017 research paper: ‘Novel application of three-dimensional technologies in a case of dismemberment’, and represented the first of 100 cases worked on by the WMG as it became a national centre for 3D printed demonstrative evidence. Many of those proceedings are still ongoing, but if they’re anything like the few Williams could divulge earlier this summer, then he and his colleagues are making a serious difference.
“You’re not squeamish, are you?”
In that first case, a murder victim had been dismembered, squeezed into two suitcases, walked through town at 21.39 as per some eerie CCTV footage, and dumped in a nearby canal. A group of workers found the suitcases, and judging their weight to be suspicious, contacted the police, who sent them to be CT scanned at the University Hospital Coventry and Warwickshire. Inside was the entire skeletal remains of a man (save for a piece of the left humerus); a saw; a kitchen knife; a hammer; and a chisel.
Humerus WMG
Elusive humerus bone: The cracking on the surface was caused by the intensity of a fire.
It’s said that dismemberment cases are not so hard to solve if you know where it happened, and thanks to one particular fire department call out, that proved true. The perpetrators, in an attempt to destroy evidence, had collected the remains, including soft tissue and that elusive humerus bone, and with the help of some plastic sheets and petrol, started an oil drum fire in their back garden.
After DNA samples from the victim’s body revealed his identity, the police were alerted to a fire where his former housemate and partner lived, put two and two together, and conducted arrests. Eleven bone elements were micro-CT scanned by the WMG, including the humerus bone which was printed and presented in court. This fragment was identified using a Nikon XT H 225/ 320LC micro-CT scanner, which highlighted the area of a clump of charcoal which had suffered the least heat damage – bone being notoriously resistant to fire. It was visualised in 50μm and printed in 20μm on an Objet 260 Connex.
“[The humerus bone] was encased in charcoal and so badly damaged that if we took it apart physically, it would have crumbled away, so we used [CT imaging] technology to scan the charcoal, extract the bone geometry, and 3D print a model to demonstrate,” explained Williams. “The only physical evidence that ties the place of murder and the murderer was this shoulder bone.”
The 3D prints not only helped the judge to determine the sentencing of the offenders – 19 and 2 ½ years respectively – but also helped in questioning. Upon seeing the 3D printed models, one of the accused cracked, admitted their guilt, and proceedings went straight to sentencing.
"A lot of people are aware of 3D printing, but not really what you can do with it."
Lifting a tray of 3D prints of this ilk out of a secure cabinet at the CiMAT, Williams’ “You’re not squeamish, are you?” query is met with a bare-faced lie. Out came 3D prints characterising leg fractures of young children; models aiding in facial reconstruction for cold cases; and finally, a segment of a skull printed on a Form 2 SLA machine.
The skull belonged to a victim who had suffered a severe beating to the head and later passed away in hospital. During a police search, a spanner and a hammer were found, and so the Nikon XT H 225/320 micro-CT scanner was again utilised to examine the skull in 80μm resolution to identify the murder weapon. Both were a match, and to present this evidence in court, the Crown Prosecution Service requested a 3D print to help them deliver the evidence. It was produced to scale in 50μm and two people were sentenced to life imprisonment.
“The benefits of this X-ray technology over conventional hospital scanners is the increase in resolution, many, many thousands time the level of detail, so we can produce very high-resolution models,” Williams stressed. “If you used a hospital scanner you would miss these microscopic injuries and fractures. That’s why the increasing resolution capability of 3D printers is great because you can include those [details].”
Domino effect
Those details being clearly described to the jury is the difference, and it is no surprise that the WMG is now working with dozens of police forces in the UK and overseas. Of equally little surprise is the businesses over in the United States sprouting up offering identical services. Lazarus 3D is a medical model company, using 3D printing technology to provide demonstrative evidence on the side, while 3D Printed Evidence is a ‘does what it says on the tin’ firm set up by a law student.
It typically costs around 1,000 USD for the digital imaging to be carried out, while a second cost for the actual 3D print is dependent on the size and materials used. But it comes as little cost to legal counsel when the chance to put the guilty behind bars or get the innocent off the hook, arises. That all depends, of course, on the jury sat to the east of their benches.
“The standard defence [against the use of 3D printing] is it either distresses the jury or influences the jury’s decision because it’s emotional,” Williams told TCT. “Presenting 3D printed parts, although accurate representation, we can do neutral colours, they’re not the real thing. They’re doing this because they can introduce it as evidence to explain to juries quite complex injuries or cases and then they can move forward.”
“It’s important to present things in a way that makes them easy to understand,” added Dr. Jacques Zaneveld, President & Founder, Lazarus 3D. “There’s a whole load of technicalities that you have to pay immense attention to, and in every step, you have to assure that there is very high accuracy. You need to be absolutely positive that what you’re building is the [accurate] representation and [you’re] able to demonstrate it.”
Not only that, they must prove to the legal authorities their competence, consistency, and reliability. The models must be accurate, repeatable, believable. The academic institutions and experts involved need to be credible. Their qualifications and track record must be ratified too.
"A powerful piece of demonstrative evidence can absolutely change the outcome of the case."
Helping WMG’s cause has been having all the scanning, data processing, image processing, and 3D printing technology all under one roof. The research it has carried out goes a long way too, as it has for Lazarus 3D, who have shown the continuity of its process has yielded accurate results across a range of cases. But the general consensus is once the technology has been accepted into the courtroom a first time, the dominoes begin to fall, case after case relies to some degree on 3D technologies, and it becomes commonplace in the courtroom.
“Hinging upon admissibility is a barrier, but really it’s just apprising the legal field of [our] services, of the technology itself, and of the applications that it has in the courtroom,” offered Josh Weinberger, Founder, 3D Printed Evidence. “A lot of people are aware of 3D printing, but not really what you can do with it, and the extent to which you can make a model, and the extent of the accuracy that you can achieve.”
WMG Warwick uni VR suite
Rendering of the skull with hammer and spanner imprints.
Beyond any reasonable doubt
Between the WMG and 3D Printed Evidence, 150 cases on both sides of the Atlantic have seen the capabilities of 3D technologies, while Lazarus 3D estimates 3D printed models for demonstrative evidence represents about 15% of its business.
“The demand is there, and the need is high,” Weinberger affirmed. “The quality of the models that we’re able to produce from this technology far surpasses the traditional models that are available. The accuracy is tremendous. We take what’s there and only remove the back wall, the trachea, some of the bone tissues. We’re not adding or altering any of the injuries by any means, we’re only highlighting what’s there so it is a true, accurate representation of the client’s injury.”
“A powerful piece of demonstrative evidence can absolutely change the outcome of the case,” emphasised Zaneveld. “Traditionally, in personal injury and medical malpractice cases, what you very often get is one medical expert saying, ‘this is a terrible injury’, and the other side saying, ‘it’s really not that bad’. And the jury is left with very little evidence that they can digest. If you present an MRI to the jury, without medical training it can be very difficult to understand and get an unbiased assessment of how much damage has occurred in that case.
“By using 3D printing, we're transforming the information present in that MRI into a way that anyone can understand. If I can show you the break in an arm and you can see how big the crack is, that's a very powerful piece that allows the jury to get a much better, independent assessment of how much injury has occurred in a way they can understand and interact with.”
“That’s the beauty of the high resolution of these 3D prints, you can see that cracking, the microscopic [injuries],” Williams finished. “These non-invasive technologies, the process of scanning and 3D printing is absolutely critical for the point where you can demonstrate to the jury. In a lot of cases, it isn’t necessary to go to 3D printing, but it’s a really important part of the process when we need it for the key cases.”
Through Standard Operating Procedures signed off by forensic regulators, and expert witness statements corroborated by prosecution and defence, these evidential articles are validated, and the floor is theirs to fight a cause, one way or the other. “Precedent is everything,” Williams summarised, “it’s only novel for so long.” As time passes, a neutral-coloured 3D anatomical model printed in high resolution will become humdrum in its presence in the courtroom, but a crucial component of many a counsel's closing statement. Beyond any reasonable doubt.
