In State v. England, 19 S.W.3d 762, 768 (Tenn. 2000), the Tennessee Supreme Court rejected a per se rule that probable cause may be established through a positive alert by a trained narcotics detection dog.
The court reasoned that the probable cause determination should turn on the dog's reliability and that the trial court should ensure that the dog is reliable by making factual findings. Id.
The court set forth the following framework for this required reliability determination:
"Accordingly, in our view, the trial court, in making the reliability determination may consider such factors as: the canine's training and the canine's "track record," with emphasis on the amount of false negatives and false positives the dog has furnished. The trial court should also consider the officer's training and experience with this particular canine." Id.