PROFESSOR ANGELA GALLOP: How cotton fibre can crack murder cases

How fluff in a trouser turn-up or cotton fibre on a shoe strap can crack even the trickiest murder cases – by forensic expert PROFESSOR ANGELA GALLOP who helped nail Stephen Lawrence’s killers

  • Crime evidence can come from ‘almost anything’ Professor Angela Gallop writes 
  • Forensic expert looked at textile fibres to help nail Stephen Lawrence’s killers
  • A tiny flake of blood was found in an exhibit bag with one of the suspects’ jackets

Most television crime dramas are the same: a bloody footprint at the scene of a murder takes us directly to the suspect, or perhaps there’s DNA beneath the fingernails of a victim or a careless fingerprint left on a door handle. Case closed.

But real forensics work is more painstaking – and fascinating. It involves a combination of laser-like observation and testing.

And the evidence we work with can come from almost anything, anywhere.

It’s just waiting to be found…

A TINY STAIN ON A BAG, BUT A VITAL CLUE TO STEPHEN’S MURDERERS

For all the recent advances in forensic technology, old-fashioned dust and fluff remain two of our most valued informants.

We use sticky tape to pick it up from surfaces, shake items in the lab to dislodge particles and use a disposable toothbrush to recover tiny traces from inside pockets, the seams of clothing and even from the inner seams of storage bags where debris has collected.

At the start of my career in the 1970s, the fashion for turn-ups on trousers proved useful. They trapped all sorts of evidence.

A meticulous search for debris was used to great effect in the cold-case investigation into the murder of 19-year-old Stephen Lawrence (pictured)

They could catch tiny shavings of sawdust used as internal packing in the construction of safes, for example. When the safe was blown open, the shavings would be scattered.

A meticulous search for debris was used to great effect in the cold-case investigation into the murder of 19-year-old Stephen Lawrence.

Stephen was waiting for a bus on a street in South-East London in April 1993 when he was attacked and stabbed to death by a group of white youths.

It was two weeks before police made any arrests, and all five suspects were then released without charge.

An inquiry commissioned by the Home Secretary found there was only weak evidence connecting any of the suspects’ clothing with Stephen.

So when I was asked to look again at the evidence, among other things we focused on a search for textile fibres that could have been transferred between the clothing Stephen had been wearing and that belonging to the original suspects.

After some success, we extended our search to the packaging in which some of the items had been stored – and discovered a tiny flake of blood in an exhibit bag containing one of the suspects’ jackets.

Clothing had been searched for blood before, but no one had thought to examine the packaging.

The flake was found to contain DNA that matched Stephen’s. Then, we found that two blue textile fibres encased within the flake of blood matched fibres from the cardigan that Stephen had been wearing.

Going back to the jacket, we were then able to locate the remains of a tiny bloodstain – indicating where the flake had come from.

It was the ‘golden nugget’ of scientific evidence that helped to solve the case.

RED SWEATSHIRT THAT CAUGHT SARAH’S KILLER

Textile fibres played an important part in convicting sex offender Roy Whiting for the murder of eight-year-old Sarah Payne.

Sarah was abducted on July 1, 2000, while playing with her siblings near her grandparents’ house in West Sussex.

Her body was found 16 days later, partially buried at the edge of a field.

Whiting was questioned within hours, but with insufficient evidence he was released after two days.

Sarah Payne (pictured) was abducted on July 1, 2000, while playing with her siblings near her grandparents’ house in West Sussex

But that was not the end of the matter. Whiting was indeed connected to the killing – by a red sweatshirt and a printed cotton curtain in his van.

Red polyester fibres matching the sweatshirt were found in combings from Sarah’s hair, and on her shoe.

A single cotton fibre with three colours along its length, caught in the Velcro fastening of the shoe, could have come from the curtain, while fibres matching a seat cover and curtain respectively were found on her body.

The dye from the sweatshirt was analysed by micro-spectrophotometry (MSP), which looks in detail at the wavelength of the colours.

The graph it produced showed the colour was largely of one type, but with an additional ‘hump’ indicating the trace presence of another colour.

Looking at other garments of the same type, none had this extra hump, which meant the batch of dye used for Whiting’s shirt was unusual. The prosecution’s case was even stronger.

Whiting was convicted in December 2001 and sentenced to life in prison, later reduced to 40 years.

HOW FLUFF FROM A SHED SOLVED DOUBLE MURDER

It was more fluff, including sweepings from the floor of a suspect’s shed, that helped solve another high-profile case.

Peter Dixon and his wife Gwenda were killed on the Pembrokeshire Coastal Path in June 1989 – a notorious crime dramatised last year in ITV’s The Pembrokeshire Murders.

The couple had been forced to disclose their cash card number, then shot at close range with a sawn-off shotgun. There were no witnesses.

In 2011 John Cooper (pictured) was given a life sentence for four murders, rape and a serious sexual assault

But amid the shed sweepings were fibres that linked a local man called John Cooper to a number of crimes.

First, it emerged that the fibres matched items of clothing that Cooper had abandoned in hedgerows after committing burglaries in the area, one of which had left two people dead.

Next, a spot of Peter Dixon’s blood was found on Cooper’s shorts.

Finally, the analysts discovered a trace of DNA matching that of the Dixons’ daughter hidden inside the upturned hem of the shorts.

The logical explanation for this was that, after the killing, Cooper had exchanged his own blood-stained shorts for a pair taken from the Dixons’ rucksack – spare clothing from the bag had been strewn about the scene.

In 2011, he was given a life sentence for four murders, rape and a serious sexual assault.

WHEN INSECTS ARE CALLED AS WITNESSES

It’s one of the very earliest crime mysteries: the fully clothed body of a farmer has been found at the side of the road with wounds to his head that appeared to have been caused by a sickle.

Gathering together the 70 men of the village, the local police officer instructs them to place their sickles on the ground at their feet.

It is a hot day, and flies are circulating. But soon they start landing on just one of the sharp sickle blades. They have been attracted by the smell of the blood.

Just as fingerprints can be identified by the shape and pattern of their loops, whorls and arches, ear prints also have identifying characteristics (stock photo used)

Told by writer Sung Tz’u, this incident took place in rural China in the 13th Century and is generally recognised as the first recorded case that used what we now describe as forensic entomology.

Today, the study of insects found on or around decomposing bodies is an essential tool in the forensic science armoury.

Often, it’s used to help estimate the amount of time that has passed since death, for example.

Insects begin to colonise a body once it has started to decompose. Their life cycle develops in four distinct phases: egg, larva or maggot, pupa and adult.

Depending on what we find, and what the weather reports say, we can work out how long the insects – and therefore the body – have been there.

WHY DETECTIVES CAN’T ALWAYS RELY ON EAR SAY

Just as fingerprints can be identified by the shape and pattern of their loops, whorls and arches, ear prints also have identifying characteristics, which include the length, width and shape of the outer ear and its constituent parts.

Sometimes an ear print is found at the scene of a crime, left during a struggle, for instance, or where a perpetrator listened at a door or window.

But there are limitations to their reliability. Appearances can be deceptive. Tests have shown it’s possible for the same ear to leave significantly different prints, and for different ears to leave very similar prints.

The killer of 94-year-old Dorothy Wood in Huddersfield in 1996 had apparently left ear prints on the window of her downstairs bedroom before climbing in and suffocating her with a pillow.

They formed a central plank of the evidence against Mark Dallagher at his trial two years later.

Dutch police officer Cornelis Van Der Lugt, a specialist in ear-print analysis, said he was convinced they were Dallagher’s. So Dallagher was convicted.

Dallagher protested his innocence throughout, and DNA profiling evidence presented at a retrial in 2003 proved the marks had, in fact, been made by someone else.

Dallagher was acquitted.

Ear prints are interesting, but they need to be better understood before they can be considered as evidence.

© Professor Angela Gallop and Jane Smith, 2022

  • How To Solve A Crime, by Angela Gallop, is published by Hodder, priced £20. To order a copy for £18, go to mailshop.co.uk/books or call 020 3176 2937 before March, 6. Free UK delivery on orders over £20.

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