Tests on unknown DNA 'not carried out'

DNA from “unknown contributors” could have been present on a reflective jacket found in the home of murder accused Steve Wright, a court has heard this morning.

Craig Robinson

DNA from “unknown contributors” could have been present on a reflective jacket found in the home of murder accused Steve Wright, a court has heard this morning.

Dr Peter Hau, a forensic scientist with an expertise in DNA profiling, was continuing to give evidence at Ipswich Crown Court.

Timothy Langdale QC, for the defence, asked Dr Hau about tests conducted on blood and semen stains on a reflective jacket found hanging in the hall way of Wright's flat in London Road.

Mr Langdale said that when low-level DNA components were detected no further tests were carried out to determine if they came from an unknown person.

Dr Hau told the court that there were already signs of another contributor but further tests would not have yielded more definite results.

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Mr Langdale said that following tests on the reflective jacket Dr Hau could not rule out that DNA from “unknown contributors” was present. Dr Hau answered: “Maybe, maybe not.”

When asked by prosecution barrister Peter Wright QC, Dr Hau confirmed that semen was found on the reflective jacket.

He said the results of the DNA components matching Steve Wright were the strongest and that it was “more likely” to have come from his semen.

Dr Hau said there was also low-level DNA not from the defendant on the jacket but that was not surprising because the surface of clothing often picks up DNA from contact with other people.

The jury was told by Dr Hau that DNA matching that of Paula Clennell and the defendant was found on the jacket.

He said there were no low level components from any other person found on the stain which picked up DNA from Wright and Miss Clennell.

The defence also asked Dr Hau about a pair of semen stained gloves found in the pocket of the reflective jacket.

Dr Hau told the court that there were a few possible cellular cells found on the finger tips of one of the gloves - but no sperm heads were detected.

Mr Langdale said that other stains found on the gloves gave “very weak and incomplete DNA profiles matching that of Mr Wright”.

He added that none of the components detected in the results from two of the stains achieved the peak height required for routine reporting purposes.

When asked by the defence Dr Hau said he could not tell if the results he found were attributable to semen or other cellular material.

Mr Langdale said: “Bearing in mind that Mr Wright was the person who normally wore these gloves, it is not surprising to pick up his DNA from them.” Dr Hau agreed.

He also asked Dr Hau about another stain that was found on the inner surface of the thumb of the left glove.

Mr Langdale said that as well as detecting a low-level DNA mixture from the stain which could have had components from Paula Clennell and Wright, the results indicated another possible component.

He said the component “could indicate a third contributor” and asked Dr Hau why it wasn't investigated further.

“It hasn't been ignored, it has been considered. In this instance it was just so low level. In my opinion it was not scientifically worth doing,” Dr Hau replied.

Dr Hau was also asked a series of questions by the prosecution about how he tests for semen, blood and saliva.

He said once he got a positive test for semen he would remove the area that it was found on and place under a microscope.

Dr Hau confirmed that a semen-stain can be deposited without detectable amounts of sperm.

Mr Wright asked Dr Hau about the amount of DNA found on the bodies of the women, in particular why more traces of DNA were found on the body of Annette Nicholls compared to Paula Clennell.

Dr Hau said that DNA was found in more locations on Miss Nicholls' body but said "it was still very small amounts of DNA".

However he said he could not really explain precisely why there was less DNA found on Miss Clennell.

Mr Wright then asked Dr Hau about what he can say as to the nature of the body fluid which left the traces of DNA on the bodies.

"In terms of the main theory as to your findings were you able to determine between semen or saliva or a mixture of both so far as the body fluid rich in DNA was concerned?," he said.

Dr Hau said he could not say for sure which body fluid had given the results.

“It was a strategic decision right at the beginning where I was expecting very little DNA on the swabs,” he said. “In order to preserve what DNA might be there I didn't have the luxury of doing a presumptive test on what the body fluid may be."

When asked he said that the results could be from semen, saliva or sweat but - based on a visual examination - it was unlikely to be blood.

Dr Hau said the contact which left the DNA on the bodies would have had to be more than simply a casual contact.

“First of all, any contact with respect to the bodies had to be (when they were) naked,” he said.

Dr Hau was then asked about DNA found on Anneli Alderton.

He confirmed that traces of semen were found which gave mixed DNA profiles matching her boyfriend and an unknown person.

He was then asked about seven blood flecks found in Wright's Mondeo car.

Dr Hau told the court that the blood came from the same source and that there was no chance of misinterpreting the findings by repeat testing because the same DNA extract was used.

He confirmed that on all the repeat testing there was no evidence of a second source of DNA.

He was then asked about gloves found in the Mondeo.

Dr Hau said four semen-stained areas were tested and that “glove a” tested positive for semen inside and outside in different locations.

In each case he said no sperm from a third party had been detected except for the glove referred to as “glove d” where Wright, Anneli Alderton's boyfriend Sam Jefford and another person could have contributed.

After lunch Dr Hau was asked about stains found on the gloves and said there had been a mixture of DNA from Wright and Miss Clennell.

Wright, 49, of London Road, Ipswich, denies murdering Tania Nicol, 19, Paula Clennell, 24, Anneli Alderton, 24, Gemma Adams, 25, and Annette Nicholls, 29, between October 29 and December 13, 2006.

The trial continues.