Nicola Bulley's dog likely went into "fight or flight mode" when she went missing, according to a canine behaviour expert.
There has been no sign of the 45-year-old mum of two since Friday, January 27, when she was last seen walking her dog on a path along the River Wyre in St Michael's on Wyre, Lancashire.
On Friday, police revealed that the main theory they were working on is that Nicola may have fallen into the river.
