A/HRC/23/31 entities without a clear legal mandate for law enforcement, including the detention of civilians by the SPLA and national security forces, remain a major concern. 26. Cases of detention of civilians by the military have been observed, even though it does not appear that the military has a general legal mandate to detain civilians. Detention by national security forces, in particular, has been used in some cases to interfere with the full exercise of other rights, such as the right to freedom of expression. In this connection, interference by military and political figures in the justice system was also noted. 27. The excessive use of force by the security forces poses a persistent problem. The shooting of unarmed demonstrators by members of the security forces in the Western Bahr el Ghazal capital of Wau in December 2012, resulting in the death of nine and the wounding of at least 17 others is an example. In other serious incidents, the shooting of civilians by SPLA members in Jonglei on 1 April 2013 resulted in the death of at least two people, while allegations were received of extrajudicial execution of 13 civilians by the SPLA in the village of Lotho in Jonglei on 4 December 2012. An investigation by the Human Rights Division of UNMISS into the incident is under way. 28. In the majority of these cases, the relevant authorities are yet to hold the perpetrators accountable for such violations. In Wau, for example, no action has yet been taken to hold those responsible for killing the demonstrators. 29. Exceptions with regard to prevailing impunity have nonetheless been noted, such as in the case of three police officers accused of raping three women in Central Equatoria, who were arrested and are to undergo trial. 30. Following a human rights investigation by the United Nations Mission in the Sudan in 2010, the Government of South Sudan took measures for accountability for past violations, including allegations of rape and killings, committed at the National Police Training Centre, as well as for the prevention of violations. Some of the individuals found responsible were removed from duty, although it remains unclear whether any further measures have been taken against them. The Human Rights Division of UNMISS engaged in a capacity-building role at the centre, where it has conducted human rights training as part of a comprehensive curriculum. The provision of technical assistance for strengthening internal accountability mechanisms is also under consideration. C. Protection of the rights to freedom of expression, association and assembly 31. UNMISS has documented a number of cases of interference with the right to freedom of expression by State authorities, including the arbitrary arrest and detention and harassment of journalists and other individuals critical of the Government. At least 18 such incidents were registered following the killing in December 2012 of the nationally renowned columnist Isaiah Abraham. In several cases, UNMISS intervened to facilitate the protection of journalists, civil society activists or human rights defenders who were believed to be under imminent threat, some of whom have been obliged to leave the country. 32. UNMISS and other partners have been working to build the capacity of journalists, civil society and other actors. At present, however, a lack of training and resources, in addition to security concerns, have limited the ability of civil society to serve as an effective watchdog for monitoring violations of the rule of law and freedom of expression. 7