Scanners employed to catalogue knife wounds

By Nina Massey, PA Science Correspondent

High-tech scanners are being used to create a “catalogue” of knife wounds that can be matched to different blades.

Detectives say the database will mean they can identify what kind of knife has been used in a stabbing, making it easier to catch criminals.

The method involves using state of the art CT scanning technology like that seen in hospitals, to create an image of the injury which can then be saved and stored.

Professor Mark Williams, from the University of Warwick’s Centre for imaging, Metrology, and Additive Technology is working with West Midlands Police to use the technology to crack crimes.

The latest technology in digital scanning and 3D printing has provided vital clues and evidence for 120 criminal cases – including murder.

Detective Chief Superintendent, Mark Payne, head of West Midlands Police CID, explained they were working with the university to build a better picture of knife wounds.

He said: “It will help us understand what type of knife has been used – so you will be able to paint an internal picture of the travel through the body of the knife

“We are also doing experimentation on cadavers and of the impact of a knife as it travels through the body.

“We are hoping to be able to be able to build a catalogue that will help investigators in the future be able to say ‘this kind of knife was used’.

“You can imagine walking into somebody’s house, and the variety of knives. It is not common for us to seize every knife in the kitchen and work our way backwards.

“It is much better than what we are currently working with, which is just kind of guess work.

Professor Mark Williams is working with West Midlands Police (Katie Neeves/WMG/The University of Warwick/PA)

“You will be to get some sort of scientific guidance in terms of the kind of knife that was used to cause knife wounds.”

He added that post-mortem examinations can disrupt a knife wound, so being able to scan a body before one has taken place will tell investigators what kind of knife has been used.

The scope for the technology to be used in criminal investigations was discussed at the British Science Festival in Coventry and Warwickshire.

Mr Payne said it had proved particularly useful in cases of strangulation where the scans had identified an area behind the hyoid bone in the neck – which often breaks when a person is strangled.

He said: “The work around the throat and the hyoid bone, has actually changed national understanding, pathologically, in terms of how the throat works, and how the hyoid bone particularly is impacted by force.

“So it has been really groundbreaking and has changed our understanding in some regards of the use of force on the body and also the way the throat reacts when it has been strangled.”

A human skull inside an X-ray Micro CT System (Katie Neeves/WMG/The University of Warwick/PA)

He added “The bone that breaks, so we thought, when you get strangled, is called the hyoid bone.

“And previous pathological understanding of the hyoid bone was that it was fused together. Actually what we have been able to show now, but the study, is that is not always the case.

“So while you can clearly see where people have been strangled, because you can see the movement in the bone, you can see the fractures in the particularly weak bone at the back of the hyoid, you can see when that has been broken.

“That is not visible to the naked eye, it is not visible pathologically. So those kind of injuries we are able to see that we couldn’t see before.”

Prof Williams explained: “It is not strictly defined as a bone but it is a bony structure formed throughout adulthood by the ‘ossification’ of cartilage within the larynx.

“It is a well-known part of the anatomy but we are characterising micro injuries that are occurring in these delicate structures caused during trauma caused by strangulation.

“They are known to happen but there is limited understanding of them available at the moment.

“We are working on building a database of 3D scans from cases that we have worked on and are in the process of publishing the results.”