As I understand it, the police are satisfied that there is no evidence that Ms Bulley left the side of the river, leading sadly to the conclusion that she in fact fell in, and her body is yet to be found.
I don;t subscribe to the notion that her dog would automatically have jumped in the river after her - she may have fainted, and an anuerism, a heart attack, a number of reasons why she may have silently fallen in, and if her dog was a distance away, he may not have noticed.