Police Dog Demonstration -- Sgt. Charles Boath, pretending to be a criminal firing a pistol, is attacked by "Earl", an Alsatian with over 20 arrests to his credit. A demonstration of the work of police dogs which was held today at the metropolitan police dog training establishment at Imber Court, included tracking, searching, chasing, and obedience tests. The dogs have proved very successful - one has nearly one hundred arrests to his credit. August 30, 1951. (Photo by Paul Popper).