Mysteries unlocked by DNA

DNA breakthroughs solved the Lynette White murder

The Lynette White case was the latest in a line of Welsh murders solved years after the crime thanks to advances in DNA science.

The evidence which eventually led to Jeffrey Gafoor's guilty plea over the brutal killing was not found until more than decade after Lynette White's death.

Advances in testing techniques - and the discovery of a new DNA sample in murder-scene flat - enabled police to build up a profile of a man who had carried out the murder of the 20-year-old prostitute.

In January 2002, South Wales Police took genetic samples from hundreds of people in the search for new leads.

The National DNA Database didn't get started until 1995 and we needed to have those things in place before we caught Jeffrey Gafoor DNA expert Andrew MacDonald

The five men originally tried for the murder were all ruled out of the new inquiry as a result of the new tests.

But the sample found in Lynette White's Cardiff flat eventually pointed to one man - 38-year-old Jeffrey Gafoor.

DNA expert Andrew MacDonald, who worked on the case at independent firm Forensic Alliance, said up-to-date DNA techniques would have ruled out the men wrongly convicted for the murder had they been available back in 1988.

Police exhume the body of Joe Kappen to carry out DNA tests

"The National DNA Database didn't get started until 1995 and we needed to have those things in place before we caught Jeffrey Gafoor," he said.

The solving of the Lynette White murder case has echoes of the 1990 murder of Geraldine Palk, also in Cardiff.

She too was brutally stabbed to death and her murder went unsolved for 12 years.

It was not until a random DNA test on inmates at Dartmoor Prison found that Mark Hampson - coming to the end of a four-year sentence for assault - matched the murderer's profile.

Breakthrough

Hampson was given a life sentence for the frenzied stabbing of the 26-year-old shipping clerk last November.

And in another DNA breakthrough last year, the 1973 murders of 16-year-olds Pauline Floyd and Geraldine Hughes at Llandarcy, near Neath, could finally be explained.

Geraldine Palk's murder was solved using DNA evidence

South Wales Police had suspected a former bus driver and nightclub doorman, Joe Kappen, who died of cancer in 1990.

Updated genetic tests on his exhumed body matched those from the Llandarcy murder scene.

At the time of the Lynette White and Geraldine Palk murders, scientists would have needed a sample of blood or semen the size of a 5p piece before being able to draw any definite conclusions using DNA testing.

These days, a single skin flake, piece of dandruff, or dab of saliva, is all that is needed to produce dependable results.

Minute traces of DNA found on the rims of cups, cigarette ends, or underwear, can provide vital clues.

Mr MacDonald added: "Techniques are getting more and more sensitive and we are getting DNA profiles out of all sorts of things that we wouldn't have got even two years ago."

Estimates suggest there are as many as 600 people in the UK who have committed murder but who escaped initial detection.

Forensic samples were taken from Lynette White's flat

More are now being caught using updated techniques - some, several decades after committing their crimes.

At the national database in Birmingham - the first DNA library of its kind in the world when it opened in 1995 - sophisticated new methods are being developed which could cut down the time detectives have to wait for the outcome of a test.

Though not 100% accurate, DNA profiles provide compelling evidence of a link between a suspect and a crime scene, or a suspect and a victim.