The first breed of police dogs ever used were German Shepherds. On top of being used by police forces, they were also adopted by the military and were used during WWI, WWII, The Korean War and The Vietnam War. Known for their size, superior intelligence and work ethic, they were well regarded.
The second most common breed was the Belgian Malinos; similar to the German Shepherd, but a little smaller and sleeker. Known for their endurance, speed, intelligence and high intensity, they’re a popular breed in Europe.
Other police dog breeds include Bloodhounds, Akitas and Belgian Sheephounds.