Regarding the search dogs. In my opinion only…. It’s very hard to interpret what the dogs used in the search for Vanessa did scent on, where and for how long, etc.
IMO, there are many variables that can impact/change odor such as subtle terrain differences, slight weather changes can cause odor to get stronger, weaker, fall, rise, etc. I’ve heard handlers joke – if only all searches for humans were in buildings with all the windows closed.
Depending on the training and skill of the dog (the handler matters big time), some dogs can stay in odor for a certain distance before they start to run into distractions, as an example. Some are just hardcharges, train often, and can pick up a broken scent trail again, maneuver from concrete, back to grass to a dirt trail without skipping a beat. For others it can be a challenge. Police K9's are excellent in doing hasty searches when they are deployed rapidly for someone (usually a fleeing bad guy but sometimes a missing person, especially small children) - in many missing person's cases for adults, this usually doesn't happen and searches can start hours later or days later.
My point, it’s just hard to say what happened in this case when the dogs were used without hearing directly from the handler and they usually, for good reason, don't speak to the press but you might get LE who says "Susie's scent was picked up and lost/stopped", that can mean so many things. IMO