In Matheson v. State, 870 So. 2d 8 (Fla. 2d DCA 2003) the Court held that "the fact that a dog has been trained and certified, standing alone, is insufficient to give officers probable cause to search based on the dog's alert." The Second District reasoned that "an officer who knows only that his dog is trained and certified, and who has no other information, at most can only suspect that a search based on the dog's alert will yield contraband. Of course, mere suspicion cannot justify a search." Id. at 13. Thus, the Second District concluded that "the most telling indicator of what the dog's behavior means is the dog's past performance in the field." Id. at 15. The Second District also discussed the issue of residual odors: In this case Razor's trainer acknowledged the tendency of narcotics detection dogs to alert on the residual odors of drugs that are no longer present. This underscores one of three central reasons why the fact that a dog has been trained, standing alone, is not enough to give an officer probable cause to search based on the dog's alert. Razor's trainer acknowledged that a trained dog, doing what he has been conditioned to do, imparts to the officer merely that he detects the odor of contraband. To be sure, as the trainer maintained, this may not be a false alert when assessing the success of the dog's conditioning. But for Fourth Amendment purposes it is neither false nor positive. The presence of a drug's odor at an intensity detectable by the dog, but not by the officer, does not mean that the drug itself is present. Id. at 13. The Second District then enunciated concerns with relying solely on evidence that the dog was trained or "conditioned" to respond in particular ways to particular stimuli: "Although we commonly refer to the "training" of dogs, manifestly they are not trained in the sense that human beings may be trained. It is not a process of imparting knowledge and skills that dogs want or need. However much we dog lovers may tend to anthropomorphize their behavior, the fact is that dogs are not motivated to acquire skills that will assist them in their chosen profession of detecting contraband. Rather, dogs are "conditioned," that is, they are induced to respond in particular ways to particular stimuli. For law enforcement purposes, the ideal conditioning would yield a dog who always responds to specified stimuli in a consistent and recognizable way, yet never responds in that manner absent the stimuli. But this does not happen. While dogs are not motivated in ways that humans are, neither can they be calibrated to achieve mechanically consistent results." Id. at 13-14. In this regard, the Second District highlighted that "conditioning and certification programs vary widely in their methods, elements, and tolerances of failure." Id. at 14. The Second District then contrasted the highly rigorous training and certification program of the United States Customs Service to the training in Matheson, where the dog and handler had undergone only one initial thirty-day certification program and one week-long annual recertification. See id. Finally, the Second District noted that dogs themselves "vary in their abilities to accept, retain, or abide by their conditioning in widely varying environments." Id. In rejecting the proposition that evidence of training and certification alone is sufficient to give probable cause to search based on the dog's alert, the Second District held that multiple factors should be considered, including the exact training received, the criteria for selecting the dogs in the program, the standards the dog was required to meet to successfully complete the training program, and the "track record" of the dog in the field, with an emphasis on the number of mistakes the dog has made. See id. at 14-15.