Forensic experts have revealed for the first time that textile fibres can be transferred between two pieces of clothing without them touching.
In small, compact and semi-enclosed spaces such as inside a lift, contactless transfer of fibres between garments can take place through the air.
In experiments using florescent clothing fibres and UV light, UK researchers demonstrated fibre transfer between two people without physical contact.
The findings have not been demonstrated before and could have major implications for fibre evidence in certain criminal cases.
Discarded fibres from a guilty suspect’s clothes are frequently used in courtrooms as proof that they were in physical contact with a victim, including in the murder trials of Stephen Lawrence and Joanna Yeates.
The new research shows that in other cases, some innocent suspects who left fibre traces may only have been in close proximity with a victim and may not have had physical contact with them.
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Textile fibres can, under certain circumstances, be transferred between clothing in the absence of contact
‘The results of the study were remarkable,’ said Dr Kelly Sheridan, who led the research at Northumbria University.
‘It not only proved that textile fibres can transfer between garments in the absence of contact, but they can do so in relatively high numbers.’
Because it has largely been assumed that fibre transfer only occurs when two surfaces touch, it is generally accepted in a case that two surfaces have been in contact at some point.
The team’s recent experiments tracked the airborne transfer of fluorescent fibres between clothing.
Two people had these fibres attached to either jumpers, long sleeved tops and fleeces that they were wearing and stood in opposite corners of an elevator.
Researchers used fluorescently tagged fibres (pictured in green under UV light) to track their airborne transfer between clothing
The elevator operated as normal and non-participants of the study entered and exited as usual.
The surfaces of the clothing were then photographed using UV-imagery techniques to determine the number of fibres that were transferred from one person to the other.
When certain conditions were met, such as enough time, garment types that are prone to shredding fibres and a close-proximity setting, airborne transfer of fibres can occur, the team say.
By matching fibres at the scene of a crime to items belonging to a suspect, investigators are able to place individuals at a crime scene
WHAT IS A FIBRE?
The FBI identifies fibre as the smallest unit of a textile material that has a length many times greater than its diameter.
More than half the fibres used in the production of textiles are synthetic, and include nylon, rayon, and polyester.
Identifying rare or unusual fibres at a crime scene has increased in significance, as it may place a suspect at the scene of the crime.
Fibres are gathered from a crime scene using tweezers, tape, or a vacuum.
Once fibres are collected, they are brought to a lab and then placed under a microscope, where they are compared against fibres from a suspected source.
Source: Crime Museum
This airborne transfer could be in potentially significant numbers for fibre types such as cotton and polyester.
As many as 66 and 38 fibres were observed in the experiments involving cotton and polyester donor garments, compared to 2 and 1 fibres in those involving acrylic and wool donor garments, respectively.
Textile fibres are one of forensic sciences’ fundamental evidence types and have been pivotal in solving some of the UK’s most notorious crimes, including the murder of black teenager Stephen Lawrence in 1993.
By matching fibres at the scene of a crime to items belonging to a suspect, investigators are able to place individuals at a crime scene.
In 2011, textile fibres, blood and hair linked to Stephen Lawrence were found on clothing seized from the men who were found guilty of his murder.
Fibres also provided key evidence in the murder of Joanna Yeates in 2010 and the Ipswich serial killings in 2006.
These circumstances offer a ‘baseline’ for forensics researchers to evaluate the likelihood of an alleged activity leading to contactless transfer of fibres.
The next step in the research will be finding out how exactly the fibres are transferred with direct contact.
‘This research shows that airborne transfer is viable in a number of case scenarios despite previous beliefs and could explain the presence of fibres on a variety of surfaces,’ said study co-author Dr Matteo Gallidabino.
‘What is equally, if not more, important, is how that fibre was transferred from one surface to another.’
Dr Ray Palmer, former senior lecturer in forensics at Northumbria University and study co-author, has given evidence at numerous high-profile trials, including that of the Ipswich serial killings and the Claremont serial killings in Western Australia.
The Claremont serial killings took place between 1996 and 1997, although a suspect was only brought to trial in November last year and is still to be sentenced.
Stephen Lawrence, pictured, was killed in a racist attack back in April 1993. Although two men were convicted of killing Stephen in 2012, the remainder of a gang of at least five white youths involved in the attack are now unlikely to ever face prosecution
‘This study was designed so that the experimental parameters were as conducive to contactless transfer as possible, whilst still maintaining a real-life scenario,’ said Dr Palmer.
‘Since there is a paucity of published studies relating to contactless transfer, the results obtained from this study will be useful to forensic practitioners as a baseline, in evaluating how likely it is that a proposed activity or case circumstance has resulted in contactless transfer.’
The study has been published in Forensic Science International.
UK forensics researcher Professor Ruth Morgan at University College London has previously highlighted the dangers of misinterpreted evidence – and how easily traces can spread from an innocent person to a crime scene.
Research led by UCL revealed 22 per cent of criminal evidence at the Court of Appeal in 2018 may have been misinterpreted.