Rain or cross contamination of the original scent item used to cue the dog is what I’ve been told are the most common reasons to lose a trail. That’s why your second question is so interesting. My guess is that they used the seat cover as the tracking scent, so JK’s scent may have been mixed in. Since Bo immediately took off from the car at the place it was parked, and JK couldn’t have made that trail, it must be the POI’s, unless the guy is super smart and, for example, puts on one of her socks to confuse things. Sounds like Bo’s pretty accurate. Tracking by trained and proven dogs actually has legal standing as evidence, and from the looks of the tracking, Bo is well trained. Some were describing him as using “improper” sniffing techniques; I’ll have to ask my guys about that one.
Your question about Bo and finding further scent at Mosaic is one that has interested me from the start. I think what Bo did at Mosaic is being kept under wraps, because the report only goes so far as to say Bo stopped at the stairwell. They don’t seem to say in any report what he did after. Did he go up the steps to the door? Was he allowed in the rest of the complex, or specific rooms? Good questions presently without answers.
Accuracy varies from dog to dog, but with a good set of conditions, accuracy can be above 85%, i.e. the trail that the dog is following is the trail of the cue scent.
Yes I have heard of scent preservation. I’ll have to ask how long a scent will “keep” under vacuum. Hope this helps.