A criminologist has detailed five possible theories behind the disappearance of Nicola Bulley as the search for the missing mum enters its seventh day.
The mortgage broker, 45, disappeared on a dog walk last Friday morning after dropping her two daughters off at school in St Michaels on Wyre, Lancashire.
Her phone, which was dialled into a work call but was on mute with the camera switched on, was found on a bench by a dog walker nearby.
Police divers using specialist equipment have been seen searching the River Wyre below where Ms Bulley's items were found on the bench.
David Wilson, emeritus professor of criminology at Birmingham City University, said police will consider five options when investigating the disappearance.
The theories include an accident, a suicide, a person going missing voluntarily, an abduction or murder.
The criminologist told the Express: "It is usually one of five things: there's been an accident of some kind; or a suicide; or a person voluntarily goes missing, they want to get away for a completely fresh start, a different life; they have been abducted or they have been murdered."
Lancashire Police have said they do not believe any crime has been committed and are treating the incident as a missing person inquiry.
Professor Wilson said in the first days of the investigation, detectives will have looked at Nicola's social media profiles, searching Facebook and looking at texts to find out any clues.
He said: "They will build up a picture of her, not just in terms of what is known about her in public, but things which might not be known, things she was keeping to herself."
The expert said police will also look at the missing mum's bank account usage, to see if any money was used just before she disappeared.
He added: "There's a belief people don't just disappear into thin air. Sadly, we have had a lot of people who have disappeared into thin air. Let's hope that even after a week there might be some light at the end of this particular investigation."
Following Nicola's disappearance, her partner Paul Ansell, her parents and sister have never stopped looking for her.
Her sister, Louise Cunningham, told Sky News: "Something has got to have been missed. Somebody must know something."
Her tearful father Ernie Bulley said Nicola's young daughters still believed it is "only a matter of time" before their mother comes home.
He told Sky: "There are two young children there waiting for their mummy to come back and we want her back obviously also, but if Nicola is out there, if she's watching this, then all we'd like to say is: 'Come home, contact the police, contact ourselves and we just want you back.'
"And they know that mummy's missing but they know that she's going to be coming home and everyone is looking for her, so it's only a matter of time, that they're thinking in their minds that she's going to walk through that door."
Mr Ansell said earlier this week the family were living in "perpetual hell".
A potential witness traced by police has said women are fearful of going out in the village where Nicola vanished.
Christine Bowman, 67, had been identified as a dog walker who may have been one of the last people to see Ms Bulley before her disappearance a week ago.
But after Ms Bowman, a retired teacher, was traced following a police appeal, she said she had already spoken to officers and "doesn't know anything".
She added: "It has made local women fearful. If they have husbands or partners, they have been taking the dogs out instead."
Lancashire Police, who have launched a huge search operation, said that despite "unanswered questions", people should not "speculate or spread false rumours" about the disappearance.
