When Aldo's officer, William Wheetley, pulled over Clayton Harris’s truck because it had an expired license plate, Harris looked visibly nervous, unable to sit still, shaking and breathing rapidly. He also had an open can of beer in the truck’s cup holder, and did not consent to his car's being searched. That doesn't stop Aldo, who was summoned over and started signalling that he smelled drugs by the driver's door handle. Wheetley concluded that gave him probable cause for a search, and while he didn't find anything Aldo normally finds, he did find, umm ...
200 loose pseudoephedrine pills, 8,000 matches, a bottle of hydrochloric acid, two containers of antifreeze, and a coffee filter full of iodine crystals—all ingredients for making methamphetamine.Harris was arrested and Mirandized, and confessed to cooking meth. Harris later challenged the arrest on the grounds that while trained, Aldo's skills were not properly verified. The Florida Supreme Court agreed, holding that objective evidence such as field performance records (showing false positives, for example) and other objective evidence about the dog's reliability were needed, given that the police only kept a log of when Aldo did correctly find contraband.
Come below the fold and learn what the Supreme Court had to say about Aldo.
Today, a unanimous Supreme Court reversed, with Justice Kagan writing the opinion allowing this dog to have his day. Basically, the Court decides, Aldo's credibility must be determined based on the totality of the circumstances, just like any other informant, and not one test:
The question—similar to every inquiry into probable cause—is whether all the facts surrounding a dog’s alert, viewed through the lens of common sense, would make a reasonably prudent person think that a search would reveal contraband or evidence of a crime. A sniff is up to snuff when it meets that test....Good dog! Here's a treat. The officer has probable cause, and the arrest stands.
[E]vidence of a dog’s satisfactory performance in a certification or training program can itself provide sufficient reason to trust his alert. If a bona fide organization has certified a dog after testing his reliability in a controlled setting, a court can presume (subject to any conflicting evidence offered) that the dog’s alert provides probable cause to search. The same is true, even in the absence of formal certification, if the dog has recently and successfully completed a training program that evaluated his proficiency in locating drugs. After all, law enforcement units have their own strong incentive to use effective training and certification programs, because only accurate drug-detection dogs enable officers to locate contraband without incurring unnecessary risks or wasting limited time and resources....
Harris principally contended in the trial court that because Wheetley did not find any of the substances Aldo was trained to detect, Aldo’s two alerts must have been false. But we have already described the hazards of inferring too much from the failure of a dog’s alert to lead to drugs, and here we doubt that Harris’s logic does justice to Aldo’s skills. Harris cooked and used methamphetamine on a regular basis; so as Wheetley later surmised, Aldo likely responded to odors that Harris had transferred to the driver’s-side door handle of his truck. A well-trained drug-detection dog should alert to such odors; his response to them might appear a mistake, but in fact is not. And still more fundamentally, we do not evaluate probable cause in hindsight, based on what a search does or does not turn up.
CHIEF JUSTICE ROBERTS: So you don't know whether -- in other words, are dogs good at sniffing things, or are they -- can they be good at bombs, but not good at meth?
MR. PALMORE: Well, I don't know the specific answer to that. I think once a dog kind of chooses a major, that's what they stick with. But I think the important point is that -
JUSTICE SCALIA: You don't want coon dogs chasing squirrels.