This was a search for a child who may still have been alive, and a suspect still at large. The cops were begging for tip-offs. Why in the fuck would they waste days or even hours with a fake search in order to "cover" for anything? Yogi worked out in the open, and he had an audience. Civilians were involved in the search, and in fact the body was actually found by a group of students who were assisting. People were able to watch the dog repeatedly lose the scent, backtrack, and pick it back up, working his way up into the canyon. That would be one hell of a dirty, dishonest performance by Yogi's handler, who by the way is still active in the K9 community.

Nobody knows exactly how Yogi did it, but given that dogs are to known smell at parts-per-trillion levels, and that there are many ways the killer's scent could be transferred to his own car tires, I don't think it requires an excess of credulity to take the police at their word.