–5– should be unconnected and separate from the agencies responsible for persons deprived of their liberty. It is essential that they are, and are seen to be, independent. In several countries, the CPT reached the conclusion that it was necessary to set up an independent agency specialising in the investigation of complaints against police or prison officers, which is demonstrably separate from the authorities having the complainants under their responsibility and from the prosecution services. 88. Whenever a complaint is considered inadmissible, complainants should be informed of the reasons by the competent complaints body and, where applicable, provided with further options for addressing their concerns. 89. Regardless of the outcome of the complaint, it is also important to ensure that complainants are not subjected to any financial or legal sanctions. 5. Traceability 90. Each establishment concerned should keep a record of complaints in a specific register, giving due consideration to the above-mentioned principles of confidentiality and safety. Such a register should include the names of the complainants, the type and the subject of complaints, the outcome of the complaints procedure and of any appeal procedure, follow-up action taken to remedy the situation complained of and any compensation provided to the complainants. These records should serve as a management tool; for instance, it may be the case that many of the complaints relate to the same members of staff, or that certain categories of persons deprived of their liberty hardly ever lodge formal complaints. 91. In each area of competence (police, prisons, immigration detention, psychiatric and social care, etc.), a national system for compiling statistics on complaints, relevant proceedings and outcomes should be established. If the data are correctly gathered and analysed, it becomes possible to identify trends and develop future policies aimed at improving the functioning of the complaints mechanisms and the accountability of the authorities entrusted with the supervision and care of persons deprived of their liberty. In this context, the absence of complaints should not be necessarily considered as positive. On the contrary, in the CPT’s experience, this is often indicative of an unsafe environment in the establishments concerned or of a lack of trust in the complaints system.