A/HRC/4/80 page 16 human rights, Sudanese who work for international organizations or who are perceived as cooperating too closely with the international community, individuals who share the predominant ethnicities of various rebel groups, and Sudanese who display opposition political views. Since May 2006 security forces have also targeted individuals who openly oppose the DPA. Sudanese who work closely with IDPs are also targeted, often on the basis of accusations that they encourage popular discontent and anti-government sentiment. 41. Since September 2006 there has been a wave of arrests of Darfurians in Khartoum. The arrests of over 30 Darfurian teachers, businessmen, journalists and university students predominately from the Fur, Masaalit and Zaghawa tribes have been carried out by the police and National Security, purportedly in furtherance of the investigation into the murder of Mohamed Taha, a prominent editor. Former detainees suggest that the murder investigation is being used as a pretext to arrest those with perceived links to rebel movements in Darfur. To date 13 detainees have been released due to lack of evidence, with three released as recently as 29 January 2007. Another three continue to be held without charge while 19 others have been charged with murder.20 42. Arbitrary restrictions on freedom of expression, association and assembly are widespread. Human rights defenders, lawyers, local leaders and political opponents voicing concerns or expressing views that are critical, of the Government, continue to be particularly vulnerable to abuses by state security agencies. The United Nations has documented numerous cases of people being harassed, arrested, detained and physically abused for voicing their human rights concerns. The victims include members of NGOs, journalists, and people who file complaints with the police or other government officials. 43. The HLM has also received credible information of torture, inhumane and degrading treatment by National Security and Military Intelligence during attacks and in the treatment of detainees. The methods used include beatings with whips, sticks and gun butts, prolonged sun exposure, starvation, electrocution, and burning with hot candle wax or molten plastic. Many detainees are held incommunicado without charge or access to a lawyer. A. Ongoing displacement and interference with humanitarian assistance 44. Ongoing attacks have resulted in massive displacement of civilians. According to the United Nations, there were 25,000 new IDPs in Darfur as of January 2007, bringing the total to over 2 million in the three regions of Darfur. We learned that there are 233,000 refugees from Darfur currently residing in Eastern Chad and receiving services from UNHCR. Many other refugees are being hosted in communities along the border. In addition to Chad, the Central African Republic has also suffered important consequences of the spill-over from Darfur.21 45. Attacks on humanitarian workers, obstacles and interference with humanitarian aid by the Government and armed militia have increased during 2006-2007. The humanitarian situation in 20 Article 130 of the Sudanese Criminal Act of 1991. 21 OCHA briefing note on the humanitarian situation in Chad, January 2007.