The search for the body of murdered teenager Danielle Jones - whose remains were hidden by her killer 16 years ago - will "take as long as it takes", according to police.
Danielle, 15, was killed after going missing after leaving her home in East Tilbury to catch a bus to school on Monday June 18, 2001, but the location of her remains have remained a mystery ever since.
Officers have now pledged to try and "identify once and for all" whether Danielle's body was hidden at a garage block in Stifford Clays, Thurrock, as they entered the second day of a fresh search at the site following a tip off that came "completely out of the blue" in February this year.
Speaking at a press conference Assistant Chief Constable Steve Worron, head of Kent and Essex Serious Crime Directorate, said: "The focus of our activity is to work with some national search specialists and forensic archaeologists to identify once and for all whether Danielle's body has been buried here for the last 16 years.
"That work will include the use of ground-penetrating radar (GPR) and there will also be some excavation work that will be undertaken following the GPR work under way at the moment."
Explaining that the search needed to be slow and methodical in order to know for sure, Mr Worron told ITV News: "Ultimately when we leave, I need to be able to speak to Danielle's family and categorically confirm to them whether or not Danielle's body has been buried here or not."
Danielle's uncle, Stuart Campbell, of Grays, Essex, was convicted and jailed for life for her kidnap and murder in December 2002, but he has never admitted how he killed his niece or where she is.
Police said only Mr Campbell knows for certain where Danielle is buried but he is still refusing to tell police or the family.
More than 1000 garages were searched between 2001-2002 around the time of Danielle's murder and more than 8500 lines of enquiry were pursued but she was never found.
The current search is now focused on a site between Goddard Road and Crammavill Street in Stifford Clays, near the home where Mr Campbell once lived.