Lancashire Police said they have "looked at and discounted" the "potential criminal element" of the disappearance of Nicola Bulley.
Mum-of-two Nicola, had just dropped off her two children at school and was walking her dog, Willow, by the River Wyre in Lancashire before she disappeared on Friday, January 27. Emergency services and members of the public have now been searching for Nicola for a total of 11 days.
Police officers said they are working on the theory that the 45-year-old , who has been described by friends as a strong swimmer, fell into the river, but that line of investigation has been questioned by friends and family. In a press conference on Tuesday, February 7, Superintendent Sally Riley said the force still believes this is the case.
READ MORE: Nicola Bulley latest: Police give press conference as search continues
She said: "It does remain our belief that Nicola sadly fell into the river, and this is a missing person enquiry. Our work around the search of the river and the river bank continues and this includes many pieces of different technical equipment.
"As I said on Friday, the river is a complex area to search, it is not a still water it is a fast flowing moving water which is tidal in parts. This makes it particularly complex. We have already discounted particular areas of the river but as they are tidal we have re-searched them to make sure nothing has been washed back into those search areas.
"We have six people searching the river banks every day, these are specially trained search officers, who are systematically, methodically searching the river bank and open ground."
Supt Riley added the National Crime Agency is also involved in the case and have overseen all the information being used by the 40 detectives investigating. The agency has not come to any different conclusions.
Lancashire Police said their extensive inquiries into the disappearance of Nicola Bulley have "so far not found anything of note".
Superintendent Sally Riley told a press conference: "Throughout this investigation... we remain fully open to any information that is credible and factual to try and trace Nicola and bring answers for her family but it does remain our belief that Nicola sadly fell into the river and that this is a missing persons inquiry.
"Any information that comes in that indicates otherwise is being checked out all the time and negated as each inquiry comes up. We're not closed in any way to any particular line of inquiry and we remain genuinely open to that.
"All these extensive inquiries however have so far not found anything of note."
She added that every potential "suspicious or criminal element" that has been raised as a line of enquiry has been "looked at and discounted."
Lancashire Police has received thousands of pieces of information from the public and have 500 active pieces of information and lines of enquiry.
As a reminder Nicola is white, 5ft 3ins tall, with light brown shoulder-length hair. She speaks with an Essex accent. She was last seen wearing a long, knee length black quilted gilet with a hood.
She had a black Engelbert Strauss coat underneath which had long sleeves and came to her waist. She was wearing tight black jeans and had long green walking socks tucked into her jeans.
She was wearing size five ankle length green wellington boots from Next. Her hair was tied into a ponytail. She was wearing a pale blue Fitbit.
Anyone with information or footage is asked to call 101, quoting log 565 of January 30.
For any immediate sightings, please call 999.
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