<blockquote>The reliability of drug dogs and their handlers is at the heart of a lawsuit filed in state district court by two Nevada Highway Patrol K-9 troopers and a consultant, who claim that the Metropolitan Police Department's police dogs, and eventually NHP's own dogs, were "trick ponies" that responded to their handlers' cues, and therefore routinely violated citizens' rights to lawful search under the Fourth Amendment.</blockquote>
via <a href="http://www.reviewjournal.com/news/crime-courts/legal-challenge-questions-reliability-police-dogs">Legal challenge questions reliability of police dogs | Las Vegas Review-Journal</a>.