Sixteen fibres and a speck of blood: The scraps of evidence which finally convicted two killers

By Daily Mail Reporter
Updated: 12:00 EST, 3 January 2012

• Private forensic investigators spent months looking for evidence after starting hunt from scratch again
• New techniques meant that tiny hairs that would have been too small to test in 1993 became crucial evidence
• Cold case success in Damilola Taylor case sparked new search
  

The successful prosecution of David Norris and Gary Dobson for the murder of Stephen Lawrence hinged on tiny traces of forensic evidence found by a cold case team.

The most important of their discoveries were 16 fibres linked to Mr Lawrence's clothes and three tiny specks of the blood.

Tiny strands of one of the killer’s hairs were also found on the victim's clothes.

Gary Dobson, left, and David Norris went on trial for the murder of Stephen Lawrence six weeks ago. Both men denied the charge

Red alert: The tiny fragment of Stephen Lawrence's blood found amid fibres of Gary Dobson's jacket

Microscopic: A slide shows blood flakes found on the jacket seized from Gary Dobson's home with a 10p coin, right, to illustrate their size

Nailed: Gary Dobson's jacket with three marked spots where scientists found three blood fragments which had less than a one in a billion chance of not being Stephen Lawrence's

To find the crucial evidence, forensic investigators at private company LGC undertook months of painstaking examination and testing.

They viewed every inch of any exhibit linked to a suspect with a microscope.

The team at LGC took a much wider approach than had been adopted before.

When examinations were carried out in 1993, it was believed that any textile fibres would have fallen off the suspects' clothes in the two weeks between the killing and their first arrest.

Blood stains or hairs also had to be of a certain minimum size for DNA profiling to be carried out.

Spotted: Tiny hairs from Stephen Lawrence (right)  that were subsequently discovered following a new search

Painstaking work: The LGC Forensics laboratory in Culham, Oxfordshire, where forensic scientists scoured every inch of Stephen Lawrence's clothing

But after successful convictions in a number of cold cases, around 2006 detectives realised that starting from the beginning could yield results.

Edward Jarman, a forensic scientist who specialises in body fluid analysis, carried out testing for blood, saliva and DNA on items of clothing seized from the suspects' homes.

In the debris from the original evidence bag holding Gary Dobson's jacket, the team found three blood fragments which had less than a one in a billion chance of not being Stephen Lawrence's.

Another blood fragment which had encased three fibres and matched Mr Lawrence's DNA to the same probability was also discovered, although only a partial profile for DNA testing was obtained.

Evidence: An LA Raiders jacket worn by Stephen Lawrence on the night he was killed. Fibres from his clothes were transferred to Gary Dobson's outfits. Two quite acrylic fibres from this jacket were found

Crucial: Four rare red-orange polyester fibres and seven quite common pink-orange fibres that matched Mr Lawrence's T-shirt (pictured above) - one of which appeared to be bloodstained

Bloody: A blue cardigan worn by the victim

When Dobson's jacket was examined all over with a low-powered microscope, a tiny bloodstain measuring 0.25mm by 0.5mm was found on the collar. This matched Mr Lawrence's DNA profile to the same probability.

HOW DAMILOLA TAYLOR COLD CASE SUCCESS SPARKED NEW SEARCH

Success in cold cases including the death of Damilola Taylor sparked a new review which uncovered key forensic evidence in the Stephen Lawrence investigation.

A team of scientists at a private company called LGC were asked to ‘start again from scratch’ in working to uncover evidence against whoever killed Mr Lawrence.

Gary Pugh, Director of Forensic Services for the Metropolitan Police, said: ‘The Damilola Taylor case...involved what LGC have done in going right back to basics and starting from scratch.

'Many of these cases have had reviews over time but quite often they're with a presumption that if nothing's been found the items aren't re-examined.

‘What I think we've done here and in previous cases is start again from scratch and that was the brief we gave LGC in this particular case.’

The case of ten-year-old Damilola Taylor, who bled to death after an attack in 2007, involved the key discovery of a blood stain on the shoe of one of the defendants.

The defence argued that the stain had been caused by saliva testing, however Mr Jarman found that when old flakes of Mr Lawrence's blood were exposed to a chemical used in the testing they became 'gel-like'.

They did not cause staining and would not absorb into the fabric.

He maintained that the most likely cause of the stain was 'primary transfer', meaning that it was caused by wet blood shed during the fatal attack.

Fibres expert Roy Green and his colleagues microscopically compared tiny fibres found on exhibits and used a machine to scientifically measure their colour.

The rarity of fibres was partly quantified by how often they occurred in a Home Office database compiled in the 1980s.

The team found a total of 16 fibres linked to Mr Lawrence's clothes on tapings - where sticky tape is passed over the garment - from Dobson's jacket and its original evidence bag.

These included four rare red-orange polyester fibres and seven quite common pink-orange fibres that matched Mr Lawrence's T-shirt - one of which appeared to be bloodstained. There were also two quite rare blue-green acrylic fibres which matched Mr Lawrence's jacket.

In debris from the original packaging of Dobson's jacket there was one red-orange fibre matching Mr Lawrence's T-shirt and a fragment of blood that contained two quite rare blue acrylic fibres that matched his cardigan.

Seven fibres were found on tapings from a sweatshirt seized from David Norris' house - six from Mr Lawrence's trousers and one from his T-shirt.

Hairs specialist Deborah Hopwood told the court that a number of short, cut fragments of hair were found on sticky tape passed over Mr Lawrence's outer clothes.

The team then discovered two tiny hairs among debris recovered from the Norris jeans - one of which was 1mm long and appeared to be bloodstained at one end. It was too small to send for DNA analysis.

The other was 2mm long and was sent to the United States to be tested for mitochondrial DNA. This is a short DNA sequence inherited from the mother and shared with anyone in the maternal line of a family.

The hair had the correct profile for the maternal line of Mr Lawrence's family. It could not be tested for nuclear DNA because the hair had no root.

Threads: A pair of green cord trousers worn by Mr Lawrence

An LGC forensic examiner's notes of exhibit LH5, a jacket found at Gary Dobson's address

Bags of evidence: Seals of all key exhibit items that was shown to the jury in the trial

Steve Allen, Managing Director of LGC Forensics said: ‘I'm extremely proud of the work that LGC's forensic scientists did on this case. Persistence, meticulous science and innovation can help convict criminals years after they committed the crime.

‘This case shows that the key to successful forensics is to assume nothing - which is all the more important in historic cases like the murder of Stephen Lawrence.’