The specialist team called in to help police look for Nicola Bulley has called off its search, saying that “if she was in the river her body would have surfaced by now”.
The announcement came just hours after Ms Bulley’s “frustrated” partner made an emotional visit to the scene of her disappearance.
Paul Ansell spent almost two hours near the river in St Michael’s on Wyre in Lancashire where Ms Bulley, 45, vanished on Jan 27 while walking her dog.
After he left, Peter Faulding, an underwater search expert, revealed that his Specialist Group International team would be stepping down. He said that despite "an extensive and thorough" search of sections of the River Wyre, he had been unable to locate Ms Bulley and he feared she “may never be found”.
“I’d have thought that she would have surfaced by now and would have been found by dog walkers – that’s my honest opinion,” he said.
“Most bodies are found by members of the public... and that’s what I’m surprised about, that Nicola hasn’t been found so far. At this point it’s open. The police are continuing their investigation.”
He added: "Although all tangible leads suggest the river, her whereabouts still remain unknown."
Specialist police divers and search teams will continue to search the river without SGI’s assistance and are now focusing their efforts on the lower estuary leading out into Morecambe Bay.
After speaking to the search team on the banks of the River Wyre, Mr Ansell was told: “She’s not here.”
He was then offered a seat in the back of an incident support van. An emotional Mr Ansell could be seen talking animatedly in the back of the van, at one point holding his head in his hands.
He stayed at the scene for around two hours, hugging family members and speaking to Mr Faulding before being driven away.
Speaking after Mr Ansell had left, Mr Faulding told the Telegraph: “He is a frustrated man because, obviously, he has no partner.
“It’s a very difficult situation to be with such an upset man. It’s tough dealing with Paul. You hear what he is going through with his kids coming home to no mum at night.”
Despite spending the past three days combing the river bed with a state of the art £55,000 sonar kit that allows them to see “every stick and stone”, the specialist search team found no sign of Ms Bulley.
“She may never be found. We don’t know. No one knows. It is unusual because usually you have some evidence. Here we have nothing. We have nothing to go on apart from a phone and a harness”, said Mr Faulding.
The team were brought in after Ms Bulley’s family disputed the police hypothesis that the most likely explanation for her disappearance was that she had fallen into the river.
Mr Faulding has claimed that Ms Bulley is not in the river and that a “third party” may be involved. He has also claimed that the phone found on the bench near to where she went missing could have been a decoy.
Superintendent Sally Riley, of Lancashire Police, previously told reporters that Mr Faulding was not included in “all the investigation detail” and knew nothing more than an ordinary member of the public.
The force has said that, despite a lack of clear evidence, the mother of two was most likely to have slipped and fallen into the River Wyre while walking her dog, Willow.
Ms Bulley was last seen at approximately 9.10am on the morning she went missing, when a witness saw her walking her dog in a field up from the spot where she is believed to have fallen in the river.
Lancashire Constabulary believe she went missing in a 10-minute window shortly after this, and is appealing to more than 700 drivers for information. IT says it has 500 active lines of inquiry.