I am still not sure about eyewitness testimony. About a year ago my husband and I were in the car and we saw our daughter. I was about to roll down the car window and call her when she disappeared in a queue of people aoutside a shop. I was so sure it was her and was puzzled as she should have been in work over 75 miles away (she lives approx 80 miles away). I wondered why she was near our house and hadn't called in to see us - this was so unlike her. So I phoned her - and guess what? She was over 75 miles away at work. She thought I had gone off my rocker ringing her, thinking she was near my house. Yet the woman we saw looked and even walked like our daughter - she was her doppelganger - the spitting image. She was the same build, same hair, and from a distance the same face! The point is, God forbid my daughter had gone missing that day, both my hubby and I would have sworn blind to the police that she was less than a mile from our house when we last saw her at 11am that same day - but she wasn't! It wasn't her - but had I not called her I was 100% certain (mistakenly) that it was her. So we can assume things and eyewitnesses can be mistaken.
I am not saying that NB was not by the riverside that day walking her dog, but the people who thought they saw her at certain times may have been mistaken, so the timeline may be off quite a bit. We know she was on the Teams call, sent texts etc, but can we really be 100% sure she was where people think they saw her at those specific times. We sometimes see things and our brain deduces what they are based on previous knowledge etc, but we can be totally wrong.
JMO