Detectives investigating Suzy Lamplugh's disappearance have launched a forensic review in the hope new technology will crack the case after 37 years.
Suzy, 25, vanished when she went to show a client who had given the name Kipper around a flat in Fulham, south west London, on July 28, 1986.
Hairs, fibres and body tissue samples found in the estate agent's abandoned car are believed to be the focus of the new scientific probe.
Former detective Jim Dickie told the MIrror last year that mystery DNA recovered from the white Ford Fiesta could belong to her killer.
Mr Dickie said a tiny sample was taken from a smudged fingerprint on the rear-view mirror.
Forensic scientists were unable to extract a profile from it in 2000 when Mr Dickie was leading the investigation but he is hopeful that it could be done now.
The ex-Met Det Supt said: "I am unaware if the DNA sample from the fingerprint has been progressed and whether there is sufficient to test it without destroying it.
"My advice from the experts was that scientific advances may improve some time in the future and DNA science may develop to enable testing without destroying it.
"I am unaware if this is still the case or a review and test have taken place and if so what the result was. Certainly up to two to three years ago this had not taken place."
A Scotland Yard spokesman refused to discuss what materials were being examined.
He said: "The investigation is still active with the most recent forensic review being this year."
The painstaking work is unlikely to be completed by the time prime suspect John Cannan has his parole hearing in September.
Convicted rapist and kidnapper Cannan, 69, is making a bid for freedom after completing the minimum term of his three life sentences for the murder of Shirley Banks in Bristol in 1987.
Cannan, who has suffered a stroke, was gravely ill last year but has improved and it is understood he is no longer being treated on the medical wing of Full Sutton jail in East Yorkshire.
If his bid for a move to open conditions is successful, it would pave the way for his release in around two years.
Suzy was officially pronounced dead 30 years ago this month. In 2002 Scotland Yard named Cannan as the prime suspect in Suzy's disappearance.
Suzy's mother Diana Lamplugh died in 2011 after being diagnosed with Alzheimer's in 2003, and her retired solicitor father Paul passed away in 2018.
The same year police completed unsuccessful searches of a property in Sutton Coldfield which once belonged to Cannan's mother. In 2019 they spent two weeks digging in Pershore, Worc, but again failed to find any evidence.
Suzy's company car was found by police in Stevenage Road at 10.01pm on the day she vanished.
It was badly parked around a mile from the flat on Shorrolds Road that she was due to show a "Mr Kipper".
The handbrake was off and her purse was still in the door pocket.
Her seat was not in its usual position but pushed further back, suggesting that Suzy may have been attacked in the car or she had not been the last person to drive it.
It was parked outside another flat being marketed by her estate agency and one theory was that she had shown her killer around that property.
The spot is close to the Thames and police frogmen searched the river in the early days of the investigation.
A woman fitting Suzy's description was seen by a number of witnesses leaving the Shorrolds Road flat with a man at around 1pm and getting into her car with him.
An artist's impression was of an "extremely smart" suspect wearing a dark suit with dark, swept back hair who bore a striking resemblance to Cannan.
He was between 5ft 7in and 5ft 9in tall, white and aged between 25 and 30.
Suzy, who was 5ft 6in tall and wearing a black jacket, grey skirt and peach-coloured blouse, was spotted by a friend with a man she didn't recognise driving north up the Fulham Palace Road at 2.45.
It is thought to be the longest running murder probe in the UK, having been actively investigated since the day she disappeared.
Mr Dickie has said he believes Cannan is also responsible for the murder of Sandra Court, 26.
The Bournemouth insurance clerk's body was found in a water-filled ditch on the Avon Causeway in May 1986.
Det Chief Insp Rebecca Reeves, the senior investigating officer, said two years ago: “The passage of time has not weakened our determination to seek justice and get the answers that the Lamplugh family continue to wait for.
"They have always been supportive of our efforts to make progress in the investigation, and they have shown remarkable strength despite the immense sadness they have endured over the years.”
Mr Dickie said on Wednesday: "When I retired from the Met in 2006 the DNA from the fingerprint in Suzy's car was the only outstanding line of inquiry and it was flagged up as something that had to be reassessed and revisited as technology became more advanced.
"The advice I was given at the time was that they couldn't do more tests on it without destroying what was left. I know they can grow the DNA like a culture now from a minute sample but it takes time.
"It might be John Cannan or it may not, but it needs to be explored. I welcome this development."
Timeline of heartache:
28 July 1986: Suzy Lamplugh disappears while showing a property to Mr Kipper in Fulham
December 1986: Suzy Lamplugh Trust established by Paul and Diana Lamplugh
October 1987: The Met Police investigation scaled down and DNA tests are conducted on 800 unidentified bodies
July 27 1993: Suzy is officially declared dead, presumed murdered.
May 2000: Police reopen case after tracing car that might have been used to kidnap Suzy
February 2001: Police search a site close to the Norton Army Barrack near Worcester.
April 2001: Police search the Quantock Hills in Somerset.
November 2002: Cannan is named as the prime suspect in the murder, but there is no prosecution due to a lack of evidence. Cannan denied any involvement.
2003: Diana Lamplugh steps down from the Suzy Lamplugh Trust after being diagnosed with Alzheimer's disease following a stroke.
August 2010: Police excavate a field near the village of Drakes Broughton in Worcestershire.
August 2011: Diana Lamplugh dies
June 2018: Paul Lamplugh dies
October 2018: Police dig a garden in Sutton Coldfield.
2019: Police spend two weeks digging in Pershore, Worc.
2023: A new forensic review begins.