- 15 20. Further, the CPT wishes to receive statistics for the period 2004 and 2005 regarding criminal and disciplinary sanctions against police officers concerning excessive or irregular use of force, as well as the number of sworn administrative examinations opened, and statistics on the follow-up taken in respect of these cases. More particularly, in light of the letter of 9 November 2005, whereby the Greek authorities informed the CPT about the opening of sworn administrative examinations in respect of the Committee’s findings in border guard stations (Ferres, Iasmos, Soufli and Tychero) and special holding facilities for aliens (Mytilini and Venna), the CPT would like to receive information on their outcome. 21. The CPT has in the past emphasised that systems for the inspection of detention facilities of law enforcement agencies by an independent authority can also make a significant contribution towards the prevention of ill-treatment of persons in custody and, more generally, towards ensuring satisfactory conditions of detention. To be fully effective, visits by such an authority should be both frequent and unannounced, and the authority concerned must be empowered to talk in private with detained persons. In its response to the 2001 visit report, the Greek authorities made reference to the Ombudsman, UNHCR and NGOs. However, with the exception of the Ombudsman, who has a specific mandate, the other organisations referred to do not have the competence or the mandate to carry out visits in the manner outlined by the CPT. In fact, during the 2005 visit, the CPT's delegation found no evidence to suggest that any independent body is regularly exercising on-thespot supervision of places of detention of law enforcement agencies. Consequently, the CPT recommends that the Greek authorities establish a system of regular visits to law enforcement establishments by an independent authority, having regard to the preceding remarks.