Mojo
Mostly harmless
The dog is trained to react to a cadaver smell. Its got a well established history of being right. You for some reason think them alerting for a cadaver is not evidence, im really confused by your logic.
The dog is trained to react to the smell of particular chemicals that are produced by cadavers, but the same chemicals can also be produced by things other than cadavers. This means that the smells can be present, and the dog can react, in places where there hasn't actually been a cadaver. I'm a little surprised that anyone would have trouble following this logic.