Police are investigating whether an un-named convicted rapist and murderer at Broadmoor secure hospital could have killed model Rachel Nickell.
Rachel Nickell was stabbed repeatedly and sexually assaulted
The 23-year-old was sexually assaulted and stabbed 49 times on Wimbledon Common, south London, in 1992.
In 1994, Colin Stagg went on trial for the murder but the case was thrown out after evidence from an undercover policewoman was ruled inadmissible.
The Met says the investigation is still open and will examine any new evidence.
In September, it was reported that a trace of DNA had been found which could rule out suspects.
Newspaper reports at the time said the sample was found when the Metropolitan Police reviewed several unsolved cases using modern scientific techniques.
The DNA is understood to be only a "partial sample", meaning it could not provide the identity of the killer.
A Metropolitan Police spokesman said on Tuesday: "The investigation into the stabbing of Rachel Nickell remains open subject to an ongoing review.
"If any new evidence was to emerge then we would act on it appropriately."