A letter report issued by the Government Accountability Office with an abstract that begins "The Drug Enforcement Administration's (DEA) Diversion Control Program is responsible for enforcing the Controlled Substances Act (CSA) and ensuring the availability of prescription drugs such as pain relievers and stimulants while preventing their diversion for abuse. The CSA requires entities handling controlled substances--such as manufacturers, pharmacies, and physicians, among others-- to register with DEA, which conducts regulatory investigations of registrants, as well as criminal investigations. GAO was asked (1) how DEA manages diversion investigation efforts, and (2) how DEA ensures policies and procedures are followed for investigations and the extent to which it determines the results of its efforts. GAO reviewed DEA policies and procedures, and interviewed DEA, state, and local officials at eleven locations which were selected on the basis of volume of cases handled, geographic diversity, and other considerations. These observations are not generalizable, but provided insights on DEA operations."