Report on the Performance of Activities of the National Preventive Mechanism for 2016 Allegations made by prisoners that they have been beaten up, are insufficiently investigated even when medical documentation exists, which is unacceptable given that such cases possibly represent violation of Articles 23 and 25 of the Constitution of the Republic of Croatia, of Article 3 of ECHR and Articles 1 and 4 of the Charter Allegations made by prisoners that they have of Fundamental Rights of the EU. In addition, been beaten up are insufficiently investigated prison system has still not created an even when medical documentation exists, atmosphere in which reporting unlawful which is unacceptable given that such cases conduct or misuse of powers, would be a possibly represent violation of Articles 23 and common practice. European Committee for 25 of the Constitution of the Republic of the Prevention of Torture and Inhuman or Croatia, of Article 3 of ECHR and Articles 1 Degrading Treatment (CPT) Standards from and 4 of the Charter of Fundamental Rights 2015, emphasize that it necessary to clearly of the EU. understand that responsibility for unlawful conduct is attributed not only to perpetrators, but also to those who were aware or should have been aware of such conduct and who failed to prevent or report it. Moreover, physicians employed by penal institutions are almost completely uninformed of their exceptionally important role when it comes to protecting human rights of persons deprived of their liberty, pursuant to international standards such as Istanbul Protocol (Manual on Effective Investigation and Documentation of Torture and Other Cruel, Inhuman or Degrading Treatment or Punishment). In November 2016, in two largest penal institutions – Lepoglava State Prison and Zagreb County Prison – we carried out an anonymous survey of prison officials, regarding their knowledge of UN revised Standard Minimum Rules for the Treatment of Prisoners (Mandela Rules). Although this being one of the most important international As much as 81 % of surveyed documents from this field, data obtained through the officials in Zagreb County Prison survey were devastating, given that as much as 81% of and 71% in Lepoglava State respondents in Zagreb County Prison and 71% in Prison, claimed that they were Lepoglava State Prison, reported that they were unfamiliar with Mandela Rules. unfamiliar with the document. Since treatment of prisoners depends directly upon the level of knowledge of their rights, it is necessary to organize intensive and systematic trainings of officials and to translate and make available all international standards pertaining to treatment of persons deprived of their liberty. Even though according to the Report on the State and Functioning of State Prisons, County Prisons and Reformatories from December 2016, the number of judicial police officials is satisfactory, the data collected during our visit shows the opposite. The noticed lack of judicial police officers directly affects not only treatment of prisoners and exercise of their rights, but also security of penal institutions. In 2016, this problem was also pointed to by Croatian Judicial Police Trade Union, emphasizing that reduced number of officials is dangerous and may represent a threat to general security. 23