German shepherds, Belgian Malinois and rottweilers are mostly trained to perform patrol duties and help prevent crime. Naturally equipped with an extraordinary sense of smell, Labradors are especially adept at drug detection and tracking down criminals or missing people. Springer spaniels, on the other hand, are typically trained to sniff out explosives and therefore particularly useful at events involving high-profile guests, such as state visits, as well as criminal investigations.

Fan says that both medical assessments of a dog's physical abilities and its temperament are taken into account before it can be assigned a role. For instance, "for patrol dogs, having a strong drive to hunt down their prey is essential," she says.

On the other hand, for sniffer dogs, having a playful nature is more critical. "We rely on positive reinforcement techniques during training, which aligns with the psychological approach we use across our programs."

The sniffer-dog training program lasts three to four months, whereas explosives detection training takes two to three months. In the early stages of the training period, dogs are rewarded with a tennis ball upon successful completion of tasks. Next they are taught how to convey the nature of their findings to their handlers. For example, they are trained to sit quietly when they have sniffed out explosives and show excitement when they find drugs.

Picking up specific scents, like that of explosives or drugs, comes next. The final phase involves putting dogs through dry runs in fictitious crime scenes.