Police will begin digging an area of land in Kettering in connection with the disappearance of a 14-year-old girl from a care home more than 21 years ago.
Sarah Benford was last seen in the Kettering area of Northamptonshire on 6 April, 2000.
A murder probe was launched three years later.
Northamptonshire Police have said they will excavate a 70m by 70m area in the town after they received “significant intelligence”.
Several suspects have been arrested since Sarah’s disappearance, but nobody has ever been charged.
Searches have also been conducted in Kettering, London and Wales.
A fresh search will begin on an area of open space land in the Valley Walk area of Kettering on Monday, following intelligence obtained by the force’s Major Investigation Team.
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Specialist search teams will be assisted by forensic archaeologists, while penetration radar equipment will be used to assess any movement on the section of land under investigation.
The site will be sealed off from the public and dozens of officers will provide scene guard support.
The excavation is expected to last two weeks.
Detective Superintendent Joe Banfield, who is leading the operation, said: “We have received significant intelligence which has pointed us to this site as a possible area of interest.
“Sarah went missing more than 21 years ago now, but we have never given up trying to find her body and, potentially, tracing her killer or killers.
“We have informed Sarah’s family and they are supportive of the operation being carried out today. We will be in close contact with them as the excavation unfolds, but we request that members of the media do not try to contact them.
“Clearly someone out there knows what happened to Sarah all those years ago and we would urge anyone with new information to contact us on 101 or, in confidence, via the Crimestoppers hotline on 0800 555111.”
Anyone with information relating to Sarah’s disappearance can contact the police, quoting incident number 359 of 10/11/2021.