Police have started searching a back garden for the body of a grandmother who is believed have been murdered.
Naheed Khan, was 43 when she was last seen in Middlesbrough in May 2018.
Specialists with a ground-penetrating radar device linked to a computer have been investigating a garden in Thornaby, Teesside.
Last month, officers appealed for a person who came forward with ‘crucial information’ to contact them again after a tip-off in November.
Neighbours said the person living at the rented house, and who was out of the property while the search was being carried out, was an elderly woman.
Cleveland Police previously questioned a 39-year-old man on suspicion of murder, and he was released pending further investigation.
Detective Inspector Louise Sproson said: ‘The search today could potentially lead detectives to Naheed’s whereabouts and is part of a series of planned searches our dedicated team will be carrying out early this year.’
Investigators were looking at 1,800 documents and 670 statements, and have 4,600 lines of inquiry to follow up, she said.
‘Someone out there knows what has happened to Naheed,’ she said.
‘I strongly believe that someone is withholding crucial information and I would urge them to come forward and assist officers with inquiries.’
Ms Khan had links to Stockton, Middlesbrough and Thornaby and is described as Asian, of slim build, around 5ft 6in, with long dark hair, the force said.
She has not been in touch with her family, despite the birth of her first grandchild, and her bank account has not been touched since she vanished.
The charity Crimestoppers has offered a £10,000 reward for information leading to the location of her body.