-53 not only where they themselves practice or condone them, but also when they transfer prisoners to other jurisdictions without ensuring that their human rights will not be violated. Important as it is, monitoring the rights of prisoners in situations of vulnerability is a serious challenge. Some persons and groups in a situation of vulnerability are difficult to identify in the course of the monitoring and to talk to, because of the stigma associated with their identity (e.g. LGBTIQ persons or some ethnic minorities) or with their crime (e.g. sex offenders). The stigma, which is often internalized, prevents vulnerable prisoners to share experiences and to talk about the root causes of their problems. This is particularly the case where the monitor visits rarely and is perceived as a “foreigner” to the system by the prisoners. The NPM monitors are sometimes perceived as government officials and this creates mistrust and suspicion, especially among vulnerable individuals who perceive representatives of the government as sources of their problems, or as accomplices of abuses of non-state actors. In some cases, the difficulty stems from the lack of appropriate expertise with in the monitoring team, especially where it has to assess the treatment of persons with specific conditions (e.g. mental or psycho-social disabilities). Monitoring the treatment of foreign prisoners, whose number has grown in EU member states, poses communication challenges, and associated problems with establishing trust and rapport with these extremely vulnerable individuals. Monitoring the rights of women and juvenile prisoners is another challenge due to the need of specific expertise and perspective in the monitoring team. 3.3. Monitoring in practice Monitoring of the rights of persons in a situation of vulnerability in prisons has a long history in Europe. At present, it is carried out by different monitoring bodies. We can distinguish three types of groups: official inspection and investigative bodies, national human rights institutions and non-governmental organizations. Each one of them adopts a specific approach. The latter depends on a variety of factors, including the aims, the monitors’ powers and their perception by the detainees. Each approach has its strengths and its weaknesses. The strength of official bodies is in Prisoners in a Situation of Vulnerability