-64 diversifies its approach to interventions trying to make use of its different levels and dimensions.94 3.3.5. Interviewing detainees in a situation of vulnerability 3.3.5.1. The role of the interview in fact-finding and some ethical considerations For the specific purposes of detention monitoring, the interview remains the key fact-finding method, and one that is used predominantly by both the international and the NPM monitors. It is particularly useful because of the flexibility which its application allows in fact-finding related to the rights of persons in a situation of vulnerability. Through the interview, the monitor aims firstly at establishing new facts. But there are also secondary aims – corroborating information received from other sources, identifying other possible sources of information and, where appropriate, establishing long-term relations with the particular respondent. At all times the monitor interviewing a person in a vulnerable situation must keep in mind the three dimensions of interviewing: epistemological (aiming at establishing or corroborating facts), ethical (involvement of the respondent in the monitor’s work as fact-finder) and safety (exposing the respondent to different risks). There are different formats of the interview (individual and group, in public and in private, confronting different stakeholders, etc.), each having its strengths and weaknesses. Article 20 of the OPCAT specifically provides for one of the formats – the “private interviews with the persons deprived of their liberty without witnesses”. This provision takes account of the particular importance of such an interview, and aims at ensuring that the authorities do not create any obstacles for it. The private interview is particularly appropriate for studying the rights of persons and groups in a situation of vulnerability as it provides for better opportunities for establishing rapport, and better ensures the respondent’s confidentiality, as well as his/her safety. The interview research usually includes several stages:95 94. See in more detail: Birk, M., W. Suntinger, “A systemic approach to human rights practice”, In: Hladschik, P. and F. Steinert (eds.), Making Human Rights Work: Festschrift für Manfred Nowak und Hannes Tretter, Neuer Wissenschaftlicher Verlag, Wien/Graz, 2019. 95. For more detail see: Kvale, S., S. Brinkmann, InterViews: Learning the Craft of Qualitative Research Interviewing, Sage, Los Angeles, etc., 2009.