Israel established the Department for the Investigation of Police Officers, known in Hebrew as Machash, in 1992 as a result of criticism for the internal handling of complaints against police. The evaluation focused on the four main objectives of all complaints systems: (1) maintaining discipline through deterrence, (2) complainant satisfaction with the investigation, (3) promoting public confidence in the police, and (4) providing feedback to police managers. Information came from official records, anonymous personal questionnaires completed by 255 police officers investigated for the illegal use of force and by 250 complainants, a telephone survey of 500 citizens, and interviews with 3 high-ranking police commanders who deal with Machash material daily. Results revealed that Machash’s deterrent capability is limited, despite some improvement, especially in comparison with the period before Machash existed. In addition, both complainants and police officers remain dissatisfied with the investigations. Moreover, the public does not know about the existence of Machash, its functions, or how to register complaints. Furthermore, police managers have difficulty obtaining material on Machash complaints for internal police purposes due to the separate civilian status of Machash. The analysis concluded that the problems will continue unless police agencies take broad organizational preventive action that involves joint civilian-police cooperation at all levels of police work and at both the individual and organizational levels. Tables and footnotes