The partner of missing Nicola Bulley says his two girls “miss their mummy desperately” and “need her back”.
The mother-of-two went missing in Lancashire on the morning of Friday 27 January while walking her dog.
Officers’ “main working hypothesis” is that the 45-year-old fell into the River Wyre near to the village of St Michael’s on Wyre.
But her family and friends have claimed there is “no evidence whatsoever” behind this.
In a new statement, released through Lancashire Police on the 10th day since Ms Bulley was last seen, her partner, Paul Ansell, said: “I have two little girls who miss their mummy desperately and who need her back.
“This has been such a tough time for the girls especially but also for me and all of Nicola’s family and friends, as well as the wider community and I want to thank them for their love and support.
“We are also really grateful to Peter and his team from SGI for coming up and helping support the work of Lancashire Police as they continue their investigation.
“If anyone has any information which could help find Nicola, I urge them to get in touch with the police and help us provide the answers we all so badly need.”
The statement comes after Specialist Group International’s dive team joined the search on Monday morning after the company originally offered its help on social media.
SGI’s chief executive, Peter Faulding, told Sky News: “Let’s get this water searched so it can be either confirmed or denied if Nicola is actually in this river.”
He said his company’s £55,000 side-scan sonar has a high frequency of 1,800 kilohertz and “we’ve got a very high hit rate” with the equipment.
Police also have a side-scan sonar but “our sonar is probably a bit more superior”, he said, adding: “I’m not sure what frequency they will be using.”
Mr Faulding said it was a “particularly long stretch of river” for police to search “because they’re doubling up as a dive team as well”.
“So it is a huge task for the police.”
