FORENSIC science was a key part of the first trial brought against Russell Bishop at Lewes Crown Court in 1987, but in the end it was not enough to convict him.

Here, Argus chief reporter Emily Walker takes a look at the crucial role modern techniques played in bringing the retrial, with evidence first presented to the Court of Appeal.

>>> Read coverage of the trial from start to finish <<<​

Advances in forensic science mean Russell Bishop has finally been convicted of the Babes in the Wood murders after 32 years of evading justice.

Forensic tests not available in 1986, when he brutally sexually assaulted and strangled Karen Hadaway and Nicola Fellows, have now found there was only a billion to one chance he was not their killer.

The new evidence conclusively placed Russell Bishop in an incriminating sweatshirt with the two nine-year-olds at the time of their murders.

The jury at Bishop’s original trial were told hairs linking the girls to their killer may have been Bishop’s, but DNA techniques were not advanced enough to prove that they must have been.

But police refused to give up on the case as technology advanced. With each scientific breakthrough detectives sent samples collected at the time back to experts to be re-examined.

Finally they proved that Bishop must have been wearing the light blue Pinto sweatshirt when the girls were killed in Wild Park on October 9, 1986.

Frustrations mounted for the girls’ families and detectives when Bishop was convicted of a strikingly similar attack on a seven-year-old girl in Whitehawk in 1990.

Bishop may have been jailed for life for her attempted murder, abduction, and sexual assault, but double jeopardy laws meant he could not be tried a second time for killing Karen and Nicola.

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As double jeopardy laws were lifted in 2003, Bishop has now become one of a tiny handful of killers to be convicted having originally been acquitted of an offence.

Law change

When double jeopardy laws were lifted in murder cases, following the Stephen Lawrence case, in 2003 detectives were granted new hope and began a fresh round of scientific testing in the hope of finding the “compelling new evidence” needed to bring a retrial.

Investigators then found damning new evidence.

New testing techniques only devised in 1999 found Bishop’s DNA on the cuff of the Pinto sweatshirt.

Forensic tests also conclusively linked the item to having been in Bishop’s home in Stephens Road in Hollingdean, and to clothing worn by Bishop’s then 16-year-old girlfriend Marion Stevenson.

A review was ordered into the evidence, and scientists from a company called Eurofins have led the re-examination of exhibits.

The company was used by the Crown Prosecution Service in the murder trial against those accused of the murder of Stephen Lawrence in 1993.

They carried out tests on the Babes in the Wood exhibits in 2013 showed DNA on the sweatshirt was a billion times more likely to have come from Bishop than from anyone else.

Post-mortem examinations were done on the girls’ bodies by pathologist Dr Iain West in October 1986.

At the time, he was looking for fibres, hairs, and other signs that might link a killer to them.

But crucially, he used scientific tape samples for the girls that remained sealed after the examinations.

Re-testing of samples taken from Karen’s arm during her post-mortem examination in 1986 also showed the DNA of a second person, with a one in 58,000 chance it was Bishop.

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A pubic hair found on the Pinto sweatshirt also matched Bishop’s DNA profile.

Paint fragments found on Nicola and Karen’s clothing matched the paint found on the Pinto sweatshirt. The original tests were done by Home Office Forensic Science Laboratory Doctor Anthony Peabody.

His reports analysed paint samples found on the blue Pinto sweatshirt, ivy hairs from the scene, and clothing fibres which matched the girls’ clothes and clothes at Bishop’s home.

Forensic scientist Dr Louisa Marsh found that the maroon paint matched Bishop’s Mini and that red paint also on the Pinto sweatshirt matched paint on the outhouses in Stephens Road.

Fibres found in 1986 on the Pinto sweatshirt were found on Nicola’s skirt jumper and knickers. A blue cotton thread found on the Pinto sweater matched Karen’s T-shirt.

At the original trial in 1987, it was considered that the forensic evidence was not strong enough to convict Bishop.

But this time, Eurofins senior scientific advisor Rosalyn Hammond was asked to consider the possibility of inadvertent transfer of fibres, materials, and DNA.

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Her tests were important to establish the reliability and the integrity of all the scientific evidence presented at the trial.

She looked at how evidence including the blue Pinto was processed, how it was handled and stored by police, and the processes used by scientists in the 1980s and today.

Original samples were all taken by December 1986. Fibres from the clothes were mounted on microscope slides, while samples from the girls were preserved in sealed scientific taping.

Exhibits from the dead girls were sealed throughout the time they were alongside the Pinto sweatshirt in the police exhibits store in John Street in Brighton in October 1986.

Conclusions

So Dr Hammond concluded: “There was no opportunity for any transfer of material during this period and there is nothing to indicate any realistic possibility of cross-contamination of exhibits during the course of examinations at the Aldermaston laboratory.”

For each piece of evidence she adopted a “worst-case scenario” approach where transfer of material could have happened.

Then from each piece of evidence she said there was either no possibility of inadvertent transfer, or the probability of it was so small that it could “effectively be discounted as a realistic possibility”.

Senior scientific advisor Roy Green who conducted the tests concluded the new evidence was “highly unlikely to be due to coincidence”.

Summarising the new forensic evidence Dr Green said: “The presence of matching fibres, paint, and hairs together with the DNA and mitochondrial DNA results provide ‘extremely strong’ support for the assertion that the Pinto sweatshirt had been worn by Bishop.

“The fibre findings provides extremely strong support for the assertion that the Pinto sweatshirt had been in Bishop’s home and that it had not been worn extensively since it was last there.

“The combination of the fibre and paint findings provide extremely strong support for the assertion that there was recent contact between the Pinto sweatshirt and Nicola, and the sweatshirt and Karen.

“The combination of advanced statistical analysis of the DNA results and the Y-STR tests provide extremely strong support for the assertions that the DNA mixture detected on Karen’s forearm taping included DNA from Bishop.

“When all the findings to date are considered together, this is what I might expect if Russell Bishop, while wearing the Pinto sweatshirt, had close contact with Karen Hadaway and Nicola Fellows at or around the time of their deaths.”

From this evidence, Brian Altman QC presented the case to the jury at The Old Bailey in London.

He told them: “There is powerful evidence of a physical connection between Russell Bishop and those girls. The person who wore the discarded Pinto sweatshirt was the killer and it was Bishop who wore it.”

>>> Read coverage of the trial from start to finish <<<​