Dual-Purpose Canines (K-9) are trained in two of three areas: detection of either narcotics or explosives, tracking and trailing, or apprehension and controlled aggression. Dual-Purpose Canines are trained to give a passive response (sit) at the source of a target odor. Each dog is trained by scent discrimination to track or trail a scent (up to hours old) across different surfaces with contamination and cross tracks to locate a specific suspect. These K-9s are prepared for operational law enforcement deployment upon completion of training.