One study notes that the U.S. Department of Justice receives more than 10,000 reports annually alleging police brutality under civil rights provisions of Federal law. In one year, however, out of 12,000 complaints, only 29 percent were actually investigated, only 50 cases were presented to a grand jury, and convictions were obtained in 16 of these cases. Regardless of the number of complaints against police, every police department must have a formal system for investigating complaints. The National Advisory Commission on Civil Disorders recommends that it be easy to make a complaint. The commission also recommends that the primary responsibility for police discipline remain within the police department, that an accessible agency outside the police department process citizen complaints, and that this agency keep the public and the police department aware of its actions and recommendations. Police departments should ensure that the complaint process is not accompanied by fear of reprisal or harassment, that the public is aware of complaint reception and investigative procedures, that all appropriate persons are notified of a complaint's final disposition, and that all complaints are recorded in a central file. The objectives of police internal investigations should focus on protecting the public and the police department, removing unfit personnel, and correcting procedural problems. In some police departments, the trial board is used as a vehicle for hearing serious disciplinary problems. In general, complaint investigation should be conducted in a manner that complies with procedural due process. 20 references, 1 table, and 3 figures