Detectives have found no evidence of a “criminal aspect or third party involvement” in Nicola Bulley’s disappearance during extensive inquiries over the 19 days since she vanished, a police chief has said.

Lancashire Police Assistant Chief Constable Peter Lawson defended his force’s investigation into the case of the missing mother-of-two at a press conference on Wednesday.

Setting out the details of the probe in more detail than police “normally” would, he said the scale has been “unprecedented”.

Nearly 40 detectives have sifted through hundreds of hours of CCTV, dashcam footage and tip-offs from the public.

And Mr Lawson said: “There is no evidence to indicate a criminal aspect or third party involvement in Nicola’s disappearance.”

Detectives have sought to combat disinformation about her disappearance amid growing speculation about what might have happened to her and criticism of the police effort.

Ms Bulley disappeared while walking her springer spaniel, Willow, in the village of St Michael’s on Wyre after she dropped her two daughters – aged six and nine – at school on January 27.

At a press conference on February 3 Lancashire Police first told the public of their “main working hypothesis” that the mortgage adviser fell in the river during a “10-minute window” between 9.10am and 9.20am that day.

The force said her disappearance is not being treated as suspicious.

Her body has still not been found and detectives extended the search for her to the sea on February 3, saying finding her there “becomes more of a possibility”.