Nicola Bulley has been missing for 10 days and her family, including her two daughters, are desperate to have her back home.
The 45-year-old mum went missing on January 27 in St Michael's on Wyre, Lancashire after dropping her children off at school.
Since then, an extensive search operation was launched but so far, no trace of her has been found in a river where police fear she fell.
Peter Faulding, the head of the private diving team Specialist Group International (SGI), said his team of experts and divers, based in Dorking, Surrey, worked with Lancashire Police and searched "three or four miles" of the river until it got dark.
"It's a negative search, no signs of Nicola," he said.
In a statement released through Lancashire Police, the mortgage adviser's partner, Paul Ansell, said: "It's been 10 days now since Nicola went missing and I have two little girls who miss their mummy desperately and who need her back."
Here is a timeline of events surrounding Nicola's disappearance:
January 27
At 8.26am Ms Bulley left her home with her two daughters, aged six and nine, dropping them off at school and engaging in a brief conversation with another parent around 15 minutes later, Lancashire Police has said.
She then took her Spaniel, Willow, for a walk along the path by the River Wyre at 8.43am, heading towards a gate/bench in the lower field.
She was seen by a dog walker who knew her at around 8.50am, and their pets interacted briefly before they parted ways, according to the force.
At 8.53am, Ms Bulley sent an email to her boss, followed by a message to her friends six minutes later, before logging on to a Microsoft Teams call at 9.01am.
She was seen by a second witness at 9.10am, the last known sighting.
Her phone was back in the area of the bench at 9.20am before the Teams call ended ten minutes later, with her mobile remaining logged on after the call.
At 9.33am, another dog walker found her phone on a bench beside the river, with Willow darting between the two.
According to police, she was wearing a black Engelbert Strauss coat, black jeans and had long green walking socks tucked into her trousers under ankle length green wellington boots.
Her hair was tied into a ponytail and she was wearing a pale blue Fitbit.
At 10.50am, Ms Bulley's family and the school attended by her children were told about her disappearance.
Lancashire Constabulary launched an investigation into Ms Bulley's whereabouts on the same day and appealed for witnesses to contact them.
January 28
Lancashire Constabulary deployed drones, helicopters and police search dogs as part of the major missing person operation.
They were assisted by Lancashire Fire and Rescue Service, as well as Bowland Pennine mountain rescue team and the North West underwater search team.
January 29
Local residents held a meeting at the village hall to organise a search for Ms Bulley at 10.30am on Sunday. Around 100 people joined the search.
Police urged volunteers to exercise caution, describing the river and its banks as "extremely dangerous" and saying that activity in these areas presented "a genuine risk to the public".
January 30
Superintendent Sally Riley from Lancashire Constabulary said police were "keeping a really open mind about what could have happened", and that they were not treating Ms Bulley's disappearance as suspicious.
January 31
Lancashire Constabulary spoke with a potential witness, a man who had been walking a small white fluffy dog near the River Wyre at the time of Ms Bulley's disappearance.
Her family released a statement saying they had been "overwhelmed by the support" in their community, and that her daughters were "desperate to have their mummy back home safe".
February 1
Ms Bulley's parents, Ernest and Dot Bulley, spoke to The Mirror about the "horror" they faced over the possibility of never seeing her again.
Her father said: "We just dread to think we will never see her again, if the worst came to the worst and she was never found, how will we deal with that for the rest of our lives."
February 2
Lancashire Constabulary spoke with a second witness who they had identified with the help of the public using CCTV but they told police they did not have any further information to aid their inquiry.
Officers from the North West Police Underwater and Marine support unit searched the area close to where Ms Bulley's mobile phone was found, while police divers scoured the River Wyre.
Meanwhile, Ms Bulley's family appealed to the public for help tracing her.
Speaking with Sky News, her sister Louise Cunningham said: "There has got to be somebody who knows something and all we are asking is, no matter how small or big, if there is anything you remember that doesn't seem right, then please reach out to the police.
"Get in touch and get my sister back."
Ms Bulley's father said his family hoped their interview would "spark a light" that would lead to her being found.
February 3
Lancashire Police said it was working on the hypothesis that Ms Bulley may have fallen into the River Wyre.
Ms Riley urged against speculation, but said it was "possible" that an "issue" with Ms Bulley's dog may have led her to the water's edge.
She urged the public to look out for items of clothing Ms Bulley was last seen wearing, and gave an extensive list.
Ms Bulley's friends also shared heartfelt appeals via television interviews, including Emma White, who told the BBC that Ms Bulley's daughters were continually asking where she was.
February 4
Ms White cast doubt on the police theory that she fell into a river, telling Sky News it was based on "limited information".
She said: "When we are talking about a life we can't base it on a hypothesis, surely we need this factual evidence.
"That's what the family and all of us are holding on to, that we are sadly no further on than last Friday."
In a Facebook post, Ms Cunningham urged people to "keep an open mind" as there is "no evidence whatsoever" that the dog walker fell in the river.
On the same day, Lancashire Police announced it wanted to trace a "key witness" who was seen pushing a pram in the area near where Ms Bulley went missing on the morning of her disappearance.
February 5
The woman described as a "key witness" by police came forward.
The force insisted she was "very much being treated as a witness" as it warned against "totally unacceptable" speculation and abuse on social media.
Reports of a private underwater rescue team set to assist police in Ms Bulley's search surfaced.
SGI, led by forensic expert Mr Faulding, offered its services free of charge.
February 6
Ms Bulley's friends said they hoped the help of a specialist underwater rescue team would give the family answers.
Speaking to broadcasters, Ms 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."
Meanwhile, Ms Bulley's partner Mr Ansell, in a statement released through Lancashire Police, said: "It's been 10 days now since Nicola went missing and 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."
Mr Faulding and his SGI team, using specialist sonar equipment to search for Ms Bulley in the river, did not find anything at the end of their first day of searching.
He said his team will look through another stretch of river on Tuesday "towards where Nicola went originally missing".
