A/HRC/42/20 in custody.39 This type of violence is widespread, with some surveys indicating that over half of the prisoners interviewed had been exposed to violence originating from fellow inmates. 40 Human rights mechanisms have repeatedly expressed their concern about the high rate of inter-prisoner violence.41 15. The presence and activities of gangs in detention facilities are the source of much of the inter-prisoner violence.42 According to some studies, such activities disproportionately contribute to this type of violence.43 The expansion of criminal organizations inside prisons has resulted in several mass killings of detainees, qualified by some as massacres, especially in the Latin American context.44 Gang violence has resulted in the death of child detainees in a number of countries.45 Also linked to the presence of gangs in prisons is the extortion by organized groups of prisoners of their co-detainees for “protection” purposes. This results in violence as those refusing to pay are often beaten, sometimes to death. 46 Inter-prisoner violence also takes the form of “disciplinary” sanctions often imposed by certain inmates on others detainees.47 16. Several human rights mechanisms have also expressed serious concern at the prevalence of sexual violence in situations of deprivation of liberty, including in immigration detention.48 Widespread inter-prisoner violence also leads persons deprived of their liberty to exchange sexual favours for protection. Women and girls in detention are extremely vulnerable to sexual violence when they are not detained separately from men and boys. Lesbian, gay, bisexual, transgender and intersex detainees, as well as inmates with a history of mental health problems, are among the persons most exposed to sexual violence and victimization from fellow inmates.49 17. Ethnic tensions between prisoners have led to clashes resulting in injuries to detainees in many facilities. 50 Discrimination between prisoners on various grounds is a frequent cause of inter-prisoner violence, resulting for instance in detainees being singled out by groups of prisoners for abusive treatment based on nationality, 51 and persons with disabilities being more exposed to violence.52 2. Contributing factors 18. Lack of adequate investigations and accountability into instances of inter-prisoner violence is an important contributing factor as it creates a climate of impunity, which results in the recurrence of this type of violence. For example, perpetrators of physical violence, including sexual violence, often only face disciplinary measures, whereas if these crimes took place outside of detention settings, perpetrators would face criminal prosecution and sanctions. 19. Acquiescence and tolerance of inter-prisoner violence by prison management and staff is highlighted as a major contributing factor by human rights mechanisms. 53 In addition to being tolerated, violence between detainees is sometimes induced by law 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 6 Submission of the International Bar Association’s Human Rights Institute. Submission of the Howard League. See CAT/C/MUS/CO/3; CAT/C/NZL/CO/6. See UNODC, Handbook on the Management of High-Risk Prisoners (Vienna, 2016); Penal Reform International, Global Prison Trends 2019; CRC/C/HND/CO/4-5; CRC/C/BRA/CO/2-4; A/HRC/11/2/Add.2. See Correctional Service of Canada, “Prison gangs: a review and survey of strategies” (Ottawa, 2009). Submission of the International Bar Association’s Human rights Institute. See CRC/C/BRA/CO/2-4; CRC/C/HND/CO/4-5. See CAT/C/GTM/CO/5-6. Submission of the Office of the Commissioner for Fundamental Rights (Hungary). See CAT/C/USA/CO/3-5; CCPR/C/CYP/CO/4. See A/HRC/36/28; CAT/C/USA/CO/3-5; CAT/C/NAM/CO/2. See CAT/C/CHE/CO/7. See CAT/C/ARM/CO/3. See CRPD/C/ARG/CO/1; A/63/175; submission of Penal Reform International. See CCPR/C/KAZ/CO/1/Add.1; CAT/C/THA/CO/1.