BECAUSE OF THE CLANDESTINE NATURE OF ILLICIT DRUG TRANSACTIONS, THE NARCOTICS INVESTIGATOR REQUIRES SOURCES OF INFORMATION BEYOND THOSE NORMALLY USED IN ROUTINE CRIMINAL INVESTIGATIONS. INFORMANTS MAY BE UTILIZED TO OBTAIN INFORMATION ON THE MODUS OPERANDI OF DRUG DEALERS, TO INTRODUCE AN UNDERCOVER AGENT TO DEALERS AND SUPPLIERS, TO MAKE DRUG BUYS AND CONDUCT NEGOTIATIONS WITH DEALERS WHICH WILL LEAD TO DRUG PURCHASES BY UNDERCOVER AGENTS, TO CONDUCT SURVEILLANCES, TO DEVELOP INTELLIGENCE INFORMATION FOR FUTURE INVESTIGATIONS, AND TO SERVE AS PROSECUTION WITNESSES IF ABSOLUTELY NECESSARY. MOTIVATIONAL FACTORS FOR INFORMERS MAY INCLUDE PAYMENT, REVENGE, OR THE POSSIBILITY OF AVOIDING OR LESSENING PUNISHMENT. INFORMERS WITH PENDING PUNISHMENT ARE PROBABLY THE MOST PRODUCTIVE AND RELIABLE INFORMATION SOURCES, AND THE DRUG OFFENDER AWAITING TRIAL IS PROBABLY THE EASIEST INFORMANT TO DEVELOP. IF AN OFFENDER-INFORMER IS TO BE USED, IT IS IMPORTANT THAT CHARGES AGAINST THE OFFENDER BE FILED AND JUDICIAL PROCEEDINGS CARRIED FORTH. REDUCTION OF BAIL AND RELEASE FROM JAIL MUST BE OFFICIALLY ARRANGED IN SUCH A WAY THAT OTHER INMATES ARE NOT AWARE THAT THE OFFENDER IS BEING USED AS AN INFORMANT. BEFORE ANY DEAL IS MADE BETWEEN THE OFFENDER AND THE INVESTIGATING OFFICER AND DISTRICT ATTORNEY, THE OFFENDER MUST BE MADE CLEARLY AWARE OF HIS RESPONSIBILITIES, THE EXTENT OF LEGAL PROTECTIONS, AND THE RESULTS HE CAN EXPECT IF HE FAILS TO PRODUCE OR DOUBLECROSSES THE OFFICER. A HARMONIOUS RELATIONSHIP MUST BE ESTABLISHED WITH THE INFORMANT. THE INFORMANT SHOULD BE GIVEN ONLY ENOUGH INFORMATION TO MAKE HIM AN EFFECTIVE OPERATOR, AND HIS IDENTITY SHOULD BE PROTECTED AND MADE KNOWN ONLY TO THE UNIT COMMANDER. CAREFUL RECORDS OF INFORMANT CONTACTS AND ACTIVITIES SHOULD BE KEPT, AND INFORMANTS MUST NOT BE ALLOWED TO USE UNDERCOVER FUNDS TO FILL PERSONAL DRUG NEEDS. INFORMANT INFORMATION SHOULD BE CHECKED AND DOUBLECHECKED. VOLUNTEER WALK-IN INFORMANTS SHOULD GENERALLY BE AVOIDED. PROSTITUTES CAN OCCASIONALLY BE VALUABLE INFORMANTS. IDEALLY, INFORMANTS SHOULD NOT BE ALLOWED TO MAKE DRUG PURCHASES. CAUTION MUST BE TAKEN TO KEEP THE INFORMANT AND THE OFFICER FROM PROVIDING GROUNDS FOR AN ENTRAPMENT DEFENSE. (JAP)