Two Key Forensic Services scientists have received commendations from North Wales Police (NWP).

They were recognised for their outstanding work in a high-profile County Lines drugs murder case that ultimately saw two men convicted and sentenced to a total of 53 years.

One of our KFS footwear experts, who is based at our Coventry laboratory, and one of our biology experts, who is based at our Warrington lab, worked on the case of Matthew Cassidy’s murder at Connah’s Quay, Flintshire, in May 2017.

Cassidy was stabbed to death in the ground floor corridor and stairwell of a block of flats by a rival drug dealer David Woods and his accomplice Leslie Baines, in a dispute over territory.

Our biology expert attended the scene from the blood/bloodstain pattern analysis (BPA) perspective and completed the blood/DNA work with her team at Warrington, while our footwear expert’s involvement came during the following July when the footwear comparison aspect was submitted to Coventry.

Our footwear expert and her team were supplied with hundreds of pre- and post-chemical treatment photographs of footwear impressions made in mud and blood on the ground-floor corridor floor and walls and up the first flight of stairs, where Cassidy suffered multiple, fatal stab wounds on the landing between the ground and first floor.

With shoes seized from the suspects for comparison, and numerous shoes and shoe prints from witnesses and emergency personnel for elimination purposes, the task was straightforward, albeit hefty – to identify and account for all footwear impressions in the images. If any of the suspect shoes corresponded to any of the impressions, an evidential comparison was required.

Shoe impressions found in blood

A link was found between training shoes seized from Baines and some impressions at the scene. Crucially, areas of two of the impressions relating to his shoes had been made in wet blood.

The only footwear seized from Woods was excluded from having made any impressions at the scene. There was, however, a set of impressions in blood unaccounted for – and it was believed these were from the ‘murderers’ shoes. Those shoes were never located.

In February 2018, our footwear expert received a request from North Wales Police for a further week or so of work. On that occasion, NWP required her to produce plans tracking the movement of the key individuals through the scene.

After a couple of solid weeks of hard work, she was able to initially extrapolate a floor plan of the ground floor/stairs of the block of flats from the hundreds of photographs supplied, and then plotted each footwear impression relating to Cassidy, Baines and the unknown shoes thought to have been worn by the murderer first on individual plans, before compiling a composite plan to reveal how the impressions related to each other.

A crucial role in the criminal justice system

It was “a huge piece of work”, with details such as direction, orientation, made in mud/blood etc recorded for each impression. Our biology expert also travelled from Warrington to Coventry to confirm which impressions were made in wet blood.

“We attended court in March 2018,” said our footwear expert. “David Woods pleaded guilty on the day we were due to give evidence, but Leslie Baines maintained his not-guilty plea, and my colleague and I both gave evidence at the trial.”

On Monday, May 21, 2018, Woods and Baines were sentenced for 27 and 26 years respectively.

Forensic scientists rarely work in isolation, with our footwear expert’s team members at Coventry also contributing substantial efforts to the case.

She added: “We individuals did nothing different in this case than each and every one of us does with every case that crosses our desks every day. We were just ‘lucky’ to work on a case where our efforts were officially recognised by the police.

“So I hope everyone will share this recognition and appreciation of the work we all do, day in, day out, and the crucial role we play in the criminal justice system.”