Lynette White 's killer has never been found

Police are hoping the test results will aid their inquiry into one of Wales's most notorious unsolved crimes.

In March, new DNA evidence confirmed the innocence of three men who were convicted of the murder but later freed on appeal.

The DNA profiles of two other men who were tried and acquitted did not match the evidence either.

Chris Mills, of London-based Network Forensics, conducted the sound tests early on Sunday morning - the time and day Ms White was killed.

Claims tested

A special detector was used to test the audibility of three different female screams, played from a CD player set up at the crime scene, a flat above a betting shop in James Street, Butetown.

Mr Mills explained the idea was to recreate as closely as possible the conditions on the night in question.

Chris Mills has helped many police inquiries

He said police were keen to establish whether witnesses who claimed to hear the victim's screams at the time in question could have done so.

"Once we've got the sound set up, we measure the sound level at different points, not only inside the flat but at various distances away from that point, towards where the witnesses would have been," he said.

"Not only will we get an idea of whether they could have heard it where they say they heard it, but how far that sound travels, and at what level you would expect to hear it."

He admitted that some aspects of the night Lynette White was murdered were impossible to recreate.

"We don't know the surrounding conditions - we do know the weather, but we don't know what condition she was in, or how loud that scream would have been.

"So you have to take a realistic view, in a natural way, to make it as near as we can to what we think happened on the evening."

Expert help

Network Forensics have assisted in many police investigations, including that into Michael Stone, the man convicted last October of the murders of Llin and Megan Russell in Kent in 1996.

They tested claims that an inmate at Canterbury Prison could have heard a confession by Stone through a cell wall.

Sound levels were tested inside and on the street

Mr Mills will submit a report to South Wales Police based on the results of his tests in Cardiff.

Detective Inspector Brent Parry said it was one of many angles of the murder inquiry.

"This isn't the only evidence that we're working on.

"We've got DNA evidence now available which we didn't have 14 years ago," he added.

"It's a matter of us working on our lines of inquiry to get the right result."

Renewed investigation

The team of 20 detectives currently working on the Lynette White case is anxious for a breakthrough.

In November 1990, three men - Yusef Abdullahi, Tony Paris, and Steve Miller - were convicted of murdering the prostitute and jailed for life.

Tony Paris offered detectives a DNA sample

But two years later, the so-called Cardiff Three were cleared by the Court of Appeal after it was successfully argued that a gross miscarriage of justice had taken place.

Two other men - John Actie and Ronald Actie - were acquitted of murder during the trial at Swansea Crown Court.

No-one else has been arrested for Lynette White's murder - although detectives have built up a profile of her killer.

The five original suspects volunteered to be tested as part of the new inquiry into the killing launched in January this year.

They have all been told that their DNA does not match the DNA profile of the murderer.