Friends of missing mother-of-two Nicola Bulley say they hope the help of a specialist underwater rescue team will give her family answers.
Private diving team Specialist Group International, led by forensic expert Peter Faulding, will help police search for Ms Bulley, who vanished while walking her dog near the River Wyre in Lancashire more than a week ago.
Police have been working on the theory the 45-year-old fell in the river but her family and friends have questioned that, saying there is still no evidence.
Speaking to broadcasters on Monday, Ms Bulley’s friend Emma White said the family asked Mr Faulding and his company for help.
She told BBC Breakfast: “Following the hypothesis of the police that Nicola was in the river, we need some evidence to back that up either way and I feel Peter and his amazing bit of kit … is going to come and sweep the river bed and give us answers.”
Speaking to ITV’s Good Morning Britain, Ms White added: “We hope they uncover nothing, like the police have done for the last 10 days, and we hope Nicola is not in that river.”
Mr Faulding said his team will use high-tech sonar, which can see “every stick and stone lying on the riverbed”.
He 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 added: “This is a particularly long stretch of river for them (police) to do because they’re doubling up as a dive team as well, so this is a huge task for the police.”
Lancashire Police believe Ms Bulley went missing in “a 10-minute window” on January 27 while walking her dog, Willow, in the village of St Michael’s on Wyre after dropping off her daughters – aged six and nine – at school.
She logged in to a Microsoft Teams call at 9.01am. The remote meeting ended at 9.30am with her phone still connected.
She was seen by another dog walker at 9.10am – the last known sighting – and police traced telephony records of her mobile phone as it remained on a bench overlooking the river at 9.20am.
The device was found by a dog walker at around 9.35am, with Willow nearby.
New images, taken from her home’s doorbell camera on the day she disappeared and released by her family, show Ms Bulley loading her car before driving her children to school.
She was wearing a long black coat and her blonde hair was in a ponytail.