Again, from a couple of books I have read on dogs, but only one was specifically about search dogs. A shoe, if worn recently would be a pretty good scent article. This is one reason dogs are noted for chewing shoes. There is a large concentration of sweat glands in a foot, and this causes a concentration of scent. The dogs chew the owner's shoes because the scent reminds them of the owner.
Now, if this shoe was not worn recently, or not at all, of course it would have been a bad scent article. It seems to me that a running shoe, if worn recently, would be a very good article because running would cause more sweat, and the friction of running would rub off more skin cells. Several sources that I have found indicate that you drop 40,000 skin cells per minute, and this is mainly what the dogs track.
The handler knows how to "read" the dog. It did not get into a track mode, but kept trying to enter the house. Of course there was a strong scent in the house, but if she left via the front door, as BC said, there should have been a track out the door and in the direction she left. The age of the trail is what is the sticky wicket here.
Would have been interesting if the dog alerted on the trunk of the car! But not knowing the history of the dog, it might not have alerted at all if untrained in human remains.
A personal gripe. It sometimes seems that things are done backwards or only partially done. I have heard of dragging for a drowning victim, then sending in divers. I dive, and I know the visibility would be poor at best, but much worse after dragging. Now, if this K9 did not find the trail, they should have called in Search Dogs and/or Human Remains dogs.
