CAT/C/HND/CO/1 page 10 ill-treatment. The State party should ensure prompt, impartial and thorough investigations into all such acts, prosecute and punish perpetrators with appropriate penalties which take into account the seriousness of their acts, and offer reparation to victims, including rehabilitation measures, as well as taking steps to prevent impunity. Human rights defenders, environmentalists and political activists 25. Despite the State party’s affirmation that interim protection measures are adopted upon the request of human rights defenders, environmentalists and political activists who claim to be in danger, the Committee is concerned about reports of persisting acts of harassment and persecution, including threats, murders and other human rights violations, experienced by human rights defenders, environmentalists and other political activists, and about the fact that such acts go unpunished (art. 16). The State party should adopt effective measures to prevent and protect human rights defenders, environmentalists and other political activists from any further violence. Furthermore, the State party should ensure the prompt, thorough and effective investigation and appropriate punishment of such acts. Data collection 26. While noting that some statistics have been provided, the Committee regrets the lack of comprehensive and disaggregated data on complaints, investigations, prosecutions and convictions of cases of torture and ill-treatment by law enforcement officials, as well as on trafficking in persons and domestic and sexual violence. The Committee also regrets the lack of statistics in respect of inter-prisoner violence (arts. 12, 13 and 16). The State party should establish an effective system to gather all relevant statistical data in order to monitor the implementation of the Convention at national level, including complaints, investigations, prosecutions and convictions of cases of torture and ill-treatment, inter-prisoner violence, trafficking in persons and domestic and sexual violence. The Committee recognizes the implications in terms of confidentiality of gathering personal data and emphasizes that appropriate measures should be taken to ensure that there is no misuse of data collected. 27. The Committee invites the State party to ratify the principal United Nations human rights treaties to which it is not yet a party, namely the Optional Protocol to the Convention on the Rights of Persons with Disabilities, the Optional Protocol to the Convention on the Elimination of All Forms of Discrimination against Women and the Optional Protocol to the Covenant on Economic, Social and Cultural Rights. 28. The Committee invites the State party to submit its core document in accordance with the requirements for the preparation of a common core document established in the harmonized reporting guidelines approved by the international human rights treaty bodies and contained in document HRI/GEN/2/Rev.5.