Swabs from murdered girl's body 'matched accused's DNA'
DNA extracted from samples from the scene of a schoolgirl's murder 40 years ago is a billion times more likely to belong to the accused than anyone else, a court has heard.
Stephen Anthony Hough, 58, is on trial for the rape and murder of 15-year-old Janet Commins in Flint in 1976.
He denies the charges, which include sexual assault and manslaughter.
Forensic scientist Alexander Peet told Mold Crown Court swabs taken from her body matched Mr Hough's DNA profile.
Mr Peet, who works for DNA testing service Cellmark, said in at least one of the samples tested, he believed the DNA originated from sperm cells.
The court heard DNA assumed to belong to Janet was also detected in one test.
In another, there were "low level" indications of a third contributor, but it was not possible to determine their origin.
Mr Peet said that reading could be "an artefact of the DNA process itself," or could be down to "tiny fragments" of DNA being introduced in the collection process.
Cross-examining Mr Peet, Patrick Harrington QC said the defence did "not dispute any of the scientific observations you make", but said there was a "paramount" need for integrity and continuity when it comes to the source of the material.
He added this was a "very unusual case and it may even be a unique case".
The court also heard evidence from Dr Christopher Lloyd, who carried out further testing after his colleague Mr Peet.
Dr Lloyd concentrated on Y-STR profiling, which focuses on the Y (male) chromosome.
He said his findings "are as I would expect if Stephen Hough had been involved in sexual activity with Janet Commins".
Although there was a very "low-level", unconfirmed result in one swab that might indicate the presence of another male, Dr Lloyd said it had "not provided any evidence" that more than one male was involved in sexual activity with Janet.
He added that, as the Y chromosome is passed on by fathers, a closely-related male on Stephen Hough's paternal line, would have a similar Y-STR profile.
Janet's body was found in a field on 11 January 1976.
One man has already served a sentence after admitting Janet's manslaughter, but he said he did not kill her.
The trial continues.