This book tells the story of the Criminal Investigation Department (CID) of the Palestine Police Force (PPF) in the historical context which impacted the CID's missions, methods, and composition. At first, the CID was engaged in providing technical assistance for criminal investigation. Following the PPF's poor performance in the Arab Revolt in 1929, a commission of inquiry, headed by Sir Herbert Dowbiggin, recommended adding intelligence gathering and surveillance of political elements to police functions. Teams were set up and a Special Branch established. From 1932 the CID deployed a network of "live sources" among the Arabs and issued intelligence summaries evaluating Arab and Jewish political activity.