Law enforcement agencies typically purchase K-9s from trainers or dealers who acquire them from Europe, where legacy blood lines have been long established. Breeds most commonly used for detection and apprehension include the Belgian Malonois, German Shepherd, Dutch Shepherd, and a variety of Labradors. Dogs can be single purpose (for apprehensions) or dual purpose for apprehensions and detection for narcotics, explosives, or cadavers. Read "K-9 Training Challenges" for more detail. Photos provided by Becki and John Johnston of AceK9.com.