Rudi unless I’m putting 2+2=5, I think they thought she’d gone into the river of her own choosing, but didn’t want to say why that was the case/their belief. Partly because i suspect they can never be 100% sure someone hasn’t snatched her, but also they didn’t want to say why they thought that, and spare the family & spouse anymore pain.
I read somewhere that the police had been called to her house the week before because there were concerns for her well-being, and noted her as ‘high risk’, which I can only see normally means a danger from spouse or themselves. In this case it appears to be from herself.
From then on in, without support from her partner & family, the Police have been made to look like idiots by sticking to the river story, when things (what was in the public domain) didn’t seem to support that.
It may have been better if they all would have come out together, early doors, in a presser and said she was suffering from ‘issues’.