Crucial questions over the forensic fibre evidence remain in the case of a man jailed for life for the murder of a 79-year-old woman, the Appeal Court has been told.
Simon Hall, now 33, of Ipswich, was jailed in 2003 for murdering Joan Albert at her home in Capel St Mary, Suffolk.
Now the Court of Appeal has reserved judgement on the case.
During the appeal forensic expert Tiernan Coyle said his research cast doubt on the only forensic link between Hall and the crime scene.
Jurors at the original trial were told that fingerprints, footprints and DNA evidence found at the scene of the murder did not match Hall's.
But clothes fibres in his car and in a cupboard at his parent's home, linked him to the murder scene, the prosecution forensic expert said at the time.
Doubts had now been raised about this evidence by Mr Coyle, of Contact Traces, the court was told.
The importance of the fibre evidence was highlighted by barrister Keir Starmer QC, now Director of Public Prosecutions, in 2007 when he told the BBC: "Simon Hall's case is really peculiar because there is no particular reason to believe he is guilty of this offence.
"The one crucial link is the fibre evidence. Break this and the case disappears."
Mr Coyle, a forensic fibre expert with 13 years experience, was asked to investigate the case by the Criminal Cases Review Commission (CCRC).
"We looked at the original fibres and conducted an independent review," he told the BBC News website.
"We found the flock fibres were not indistinguishable (as the court had been told in the original trial) but were different.
"I was very surprised. I fully expected to be confirming what the Forensic Science Service had done.
"The flock fibres were of a different thickness, and different colour and different number of titanium particles in them."
Titanium particles are added to cloth to make it less shiny.
Mr Coyle's research also found that the pigment fibres were carbon black, "making them low in value evidentially" as the use of this dye is very widespread.
He then double-checked his findings with a larger sample of the fibres taken by police and this confirmed his view.
During the hearing, Ray Palmer, of the Forensic Science Service, insisted his own re-examination of the fibres "bolsters the initial findings", that fibres linked Hall to the scene.
He said the First Derivatives (FD) technique used by Mr Coyle - used to statistically analyse the presence of chemicals in fibres - exaggerated small differences, sometimes finding differences in fibres known to be from the same source.
But when cross-examined by Michael Mansfield QC for Hall, Mr Palmer admitted small differences in fibre analysis can be important and the FD technique can be helpful.
Mr Coyle also found evidence not picked up by the original forensic investigation.
"We found fragments of foam in the tapings which could have been from gloves - found in the same place as the fibres," said Mr Coyle.
"It raises the possibility that the offender was wearing gloves."
Mr Coyle said he found it bizarre that during the Appeal Court hearing, the Crown said the foam may have come from a forensic scientist, suggesting the evidence was contaminated by a member of staff.
Mr Coyle also found "colourless cotton fibres which we see in grey fleeces such as sports material (clothing)", not found in the original investigation.
He said he was happy to help Suffolk Police with any reinvestigation into the case.
The first doubts about the fibre evidence were raised by researcher Gabe Tan and the Innocence Project, which is based at the University of Bristol and headed by Dr Michael Naughton.
Dr Naughton said there were serious questions to be raised in the way fibre evidence was used in this case.
"We need to be reviewing the use of fibre evidence - it is not reliable," he said.
David Jessel, a former commissioner with the CCRC, said he had concerns about the case from the beginning.
He said there appeared to be "very, very strong forensic evidence even though there was so much against a conviction and he had no motive".
The role of the CCRC was to look into the forensic evidence of the fibres and the decision was then made to send the case back to the Court of Appeal.