21 – to allow to conduct private interviews with the persons deprived of their liberty without witnesses, whether in person or with the assistance of interpreter, if this is found necessary, including with any other person the Sub-committee for Prevention of Torture believes is able to provide relevant information; – to enable it unrestricted access to all information concerning the number of persons deprived of their liberty in places of detention, including the number of places and their location, unrestricted access to all information referring to the treatment of those persons and their detention conditions, as well as to provide any relevant information the Subcommittee on Prevention of Torture may request to evaluate the needs and measures that should be adopted to strengthen the protection of persons deprived of their liberty against torture and other cruel, inhuman or degrading treatment or punishment; – to review the recommendations of the Sub-committee for Prevention of Torture and enter into a dialogue with it about possible implementing measures.40 The Sub-Committee on Prevention of Torture hasn’t visited Serbia yet. 3.2. National Preventive Mechanisms (NPM) The Optional Protocol stipulated that Each State Party shall set up, designate or maintain at the domestic level one or several national visiting bodies for the prevention of torture and other cruel, inhuman or degrading treatment or punishments41.42 NPM shall be entitled to: – the access to all data about the number and treatment of persons deprived of their liberty at the institutions where they are placed and the number of institutions and their location; – access to all detention institutions, their installations and facilities, as randomly selected by it; – unobstructed interviews with persons deprived of their liberty without the presence of witnesses, either personally or with the presence of an interpreter, where required and any other person NPM may believe could provide relevant information, at their free choice.42 NPM is authorized to regularly check the treatment of persons deprived of their liberty in the places of detention, and to issue its recommendations to the competent authorities aimed at improving the treatment and status of persons deprived of their liberty and preventing torture or other cruel, inhuman or degrading treatment or punishment, taking into account all 40 Optional Protocol, Article 12 and 14 41 Optional Protocol, Article 3 42 Optional Protocol, Article 20