A/HRC/33/37 members of the ruling party’s youth wing, the independent experts refrained from carrying out investigations at some sites to protect witnesses and victims. While initial access to government officials was relatively good, it deteriorated over time. 9. Several government officials said they were not in a position to provide information, but would do so in writing afterwards. By a letter dated 19 July 2016, the independent experts addressed specific questions to the Government, to which they followed up by a letter dated 1 September 2016. In that last letter, they also offered to provide technical capacity to document the alleged mass graves. Regrettably, no response was received until the day when the report was completed; the response consisted of a blanket denial of all violations. 10. Despite the constraints, the independent experts were able to collect and verify enough information to substantiate their conclusions. II. Methodology 11. The independent experts conducted a total of 227 interviews, in some cases with multiple parties. Among those interviewed were government officials, politicians and members of civil society in Bujumbura, Muramvya and Gitega. The independent experts also conducted field visits to the Democratic Republic of the Congo, Rwanda, Uganda and the United Republic of Tanzania to interview, among others, 182 refugees. Following an online call for submissions website,1 the independent experts received 57 submissions. An extensive review of other relevant material, including reports by the United Nations and international and national human rights organizations, was carried out. III. Legal framework 12. The independent experts discharged their mandate against applicable standards of international human rights law, international criminal law and international refugee law, as well as the Constitution of Burundi and other domestic laws. 13. Under international human rights law, States are required to respect human rights and to ensure that their own representatives do not violate those rights, for example by using unwarranted force. States are also responsible for the actions of non-State actors that may be attributed to them, for example informal groups that operate with their endorsement or acquiescence. 2 States must moreover protect those within their jurisdiction against human rights abuses by non-State actors. In addition, States must, at a minimum, ensure accountability for gross human rights violations and abuses. 3 If a State fails to ensure accountability for the arbitrary deprivation of life, such a failure in itself constitutes a separate violation of the right to life. 4 14. Burundi has ratified a number of human rights treaties, including the International Covenant on Civil and Political Rights (1990), the International Covenant on Economic, Social and Cultural Rights (1990), the Convention against Torture and Other Cruel, 1 2 3 4 4 See www.ohchr.org/EN/HRBodies/HRC/UNIIB/Pages/UNIIB.aspx. See General Assembly resolution 56/83, annex, chap. II. Article 2 (3) of the International Covenant on Civil and Political Rights. Human Rights Committee, general comment No. 31 (2004) on the nature of the general legal obligation imposed on States parties to the Covenant, para. 18. See also African Commission on Human and Peoples’ Rights, general comment No. 3 (2015) on the African Charter on Human and Peoples’ Rights: the Right to Life (art. 4), para.15.