Police began excavating a meadow today in the hunt for the body of murdered estate agent Suzy Lamplugh.
Officers used a mechanical digger to create a shallow trench in a field off the B4084 between Pershore and Drakes Broughton, in Worcestershire.
They were preparing to use ground-penetrating radar to examine the earth for evidence it was disturbed more than 24 years ago.
Two forensic experts, Professor David Hawksworth and Patricia Wiltshire, were at the scene advising officers on the search.
Miss Lamplugh, 25, disappeared in July 1986 after leaving her west London offices to meet a mystery client known only as Mr Kipper.
On the day of her disappearance, witnesses reported seeing her argue with a man outside a property in Shorrold Road, Fulham.
Her white Ford Fiesta was later found a mile and a half away. She was declared dead, presumed murdered, in 1994.
Officers have examined thousands of lines of inquiry and conducted DNA testing on 800 unidentified bodies.
Although the case ground to a halt in October 1987, the file remained open and the investigation was actively restarted in 2000.
Detectives have apologised for "significant opportunities" which were missed during the first inquiry.
The latest search comes after a potential witness said he saw a mound of earth there around the time Miss Lamplugh vanished.
It is several miles from disused military barracks at Norton which were searched by a team of police officers in December 2000.
The area has been linked to prime suspect and convicted killer John Cannan, of Sutton Coldfield. It has been claimed his prison nickname was "kipper".
Cannan was released from a hostel days before Miss Lamplugh disappeared and a former girlfriend told police he suggested the body was at the barracks.
He has been questioned several times but in 2002 prosecutors said there was not enough evidence to charge him.
Miss Lamplugh's parents Diana and Paul founded a charity in their daughter's name and spent years raising public awareness on personal safety.
Mr Lamplugh, 79, said friends and relatives were following the investigation closely but were being careful not to get their hopes up.
He said: "The police have kept me fully informed and I look forward to further information with interest."
A Scotland Yard spokesman said: "Officers investigating the disappearance of Suzy Lamplugh will be carrying out a search on Tuesday of a small area near Pershore in Worcestershire.
"The Met remains committed to solving the Suzy Lamplugh case and we will continue to work towards this end. We will follow up any information in relation to this case."
Locals said the meadow at the centre of the latest search lies alongside a small stream and is often flooded.
Two vans and a four-wheel drive vehicle were parked on the edge of the site as officers used surveying equipment to examine the land.
University of Gloucestershire academic Professor Hawksworth is an expert mycologist and environmental scientist.
Mrs Wiltshire, of the University of Aberdeen, is an expert in decomposition and microscopic evidence left in graves such as pollen and fungi.