MacCrehan says it’s important to use vapors in training because they have the same compounds as the actual explosive. Using live explosives in training is expensive, complicated, and dangerous.
But not using real explosives has its costs because training with synthetic explosives isn’t as accurate. In court, a dog’s findings can often be discounted if it was not trained on real explosives, or if doubt can be cast on the dog’s findings based on the lack of training standards or other related issues.
A recent Supreme Court decision that permitted the findings of a drug-sniffing dog to be used as evidence shows that courts are slowly becoming more receptive to allowing canine-found evidence. In that case, a drug-sniffing police dog in Florida alerted his officer to the scent of drugs on a vehicle during a traffic stop. In a unanimous decision, Supreme Court justices ruled in Florida v. Harris that drug- or bomb-detection dogs can give police probable cause to search private property if they alert officers to potential illegal activities.
MacCrehan says that dogs provide an important alternative to technological explosives detection. “Swipes are great for portals like airports, where people are going through and you can swipe the handle of their luggage and catch them in the act,” he says. “But if you had 300 people with swipes and instruments, they could work a building for a month before they could have found where the explosives were. The dogs can do it in a matter of 10 minutes.”