The pharmacist, whether directly involved or not, is in a position to identify physicians who write an unusual number of prescriptions for controlled substances. The record of prescription sales maintained at the pharmacy form an important part of the investigation. Pharmacy files may contain forged prescriptions created by the pharmacist. Drug Enforcement Administration (DEA) officials estimate that a large volume of forged prescriptions divert pharmaceuticals into illegal channels. A common complaint from pharmacists who attempt to thwart forgers of prescriptions as they have them filled is that police officers do not respond promptly to calls for assistance. Patrol officers must understand that prescription forgery is an important and immediate call for assistance. With assistance from the DEA, several States have developed Diversion Investigation Units (DIU). The units are partnerships of State, local, and State medical licensing board officials. Either the DIU of a specialized narcotics investigation unit within the local police department should be used for assistance and guidance by patrol officers who recognize possible drug diversion cases. Identification of drugs, appropriate charges, and insight into required elements of proof are obvious areas for cooperation. Seven tips to help identify possible forgers are presented. A discussion guide and a short quiz are included.