A/HRC/42/CRP.1 27. Primary responsibility for protecting victims, witnesses and other persons cooperating with the Group of Experts rests with their States of residence and nationality. The Group of Experts thanks the victims and witnesses who shared their experiences. 28. In line with existing United Nations policies on information sensitivity, classification and handling, information provided by witnesses and other confidential materials have been classified as strictly confidential.4 D. 1. Sources of evidence, methods of conducting interviews, and access constraints Methods of collecting evidence and access constraints 29. The Group of Experts reviewed a substantial quantity of primary and secondary source information, including conducting more than 600 interviews with victims and witnesses during the investigative period following extension of its mandate in September 2018. The Group ensured insofar as possible that interviews were inclusive of gender perspectives and encompassed a wide range of gender, ethnic, religious, political, and geographic representation, both overall and with respect to the particular incident or pattern of conduct under review. Interviews were conducted in person whenever possible, in a safe and private setting and in the presence of a trusted, professional interpreter where required. Other interviews were conducted remotely, through secure channels of communication and taking additional precautions to ensure reliability and the safety of the interviewee. 30. The findings in this report are based on the independent investigations conducted by the Group of Experts. Where available and appropriate, the Group additionally examined information from other sources as part of the process of reviewing relevant corroborating or exculpatory evidence. The Group of Experts reached independent conclusions on such content, both for individual incidents and where it was useful for the purposes of determining whether such conduct was part of a pattern. In all cases where the Group examined external information on incidents and patterns of conduct, it made its own independent conclusions after assessing the reliability of the information and the credibility of the sources from which it came. 31. In 2018, when the Group of Experts and members of the secretariat were granted access to Yemen, visits were undertaken to Aden, Sana’a, Sa’dah and al-Hudaydah. Visits were also undertaken in 2018 to Djibouti, the Hashemite Kingdom of Jordan, the Kingdom of Saudi Arabia, and Switzerland. 32. Through visits to Yemen and countries hosting displaced Yemenis in 2018, the Group of Experts and its secretariat conducted in person interviews with victims, witnesses and others with direct information about incidents and patterns of conduct occurring in Yemen since September 2014. The Group of Experts further supplemented the in-person interviews with interviews using remote methods. Although the Group of Experts and secretariat faced significant security, logistical and administrative constraints in arranging some of the planned visits to Yemen in 2018, and ultimately were unable to visit all the affected governorates (notably Ta’izz), the visits to Yemen and neighbouring countries provided ample direct and secondary evidence related to the Group’s mandate. 33. Regrettably, the Group of Experts faced considerable constraints to its work following the release of its first report in August 2018, after which the Experts and the secretariat were not granted visas by the Government of Yemen or the Kingdom of Saudi Arabia. Despite these constraints, the Group of Experts undertook visits to other countries to meet displaced Yemenis in 2019. It followed ever-evolving best practices learnt from other fact-finding bodies facing access constraints, and managed to gather a mass of reliable and credible evidence upon which to base its findings. The Group, for example, conducted in person interviews outside of Yemen with victims, witnesses and others with 4 Secretary-General’s bulletin on Information sensitivity, classification and handling, ST/SGB/2007/6. 9