A/HRC/15/33 cases. In Argentina, a new witness protection bill proposes the establishment of a dedicated unit to address witness protection issues relating to trials for crimes against humanity.50 50. No matter the placement of the witness protection agency, the law should ensure that the witness protection body enjoys full organizational and financial independence in the exercise of its functions. (iv) Staff selection and vetting process 51. The law should explicitly indicate the process for selecting staff to work in the agency, which should be based on strict criteria of competence and integrity. A broader vetting process may also enhance the security of witnesses, and would be important particularly in post-conflict situations where the State takes the initiative to deal effectively with past abuses of human rights. (v) Eligible crimes 52. The law should identify the crimes for which witness protection measures should be envisaged. Such crimes should include all gross violations of human rights and serious violations of international humanitarian law, since perpetrators of such violations may be in official positions which allow them to harm or intimidate witnesses.51 (vi) Mandate to protect and assist 53. The mandate of the agency should include protection, in the form of provision of physical security, and necessary assistance, such as psychological, medical and legal assistance, which witnesses may need. These two aspects are inter-related, and an approach excessively focused on physical security has been found to alienate witnesses. At the same time, the distinction between protection and assistance should not be blurred, and witness protection agencies should establish separate sub-entities to deal with each aspect, so that witnesses know exactly where to go to address their needs. 54. Witness protection programmes in many States often limit their programmes to relocation and change of identity, leaving other measures to ordinary police services, while the laws of some States contain an exhaustive list of protection measures available, from concealment of the identity of the witness in judicial acts prior to the trial to change of identity and relocation. Indeed, a broad range of measures is necessary if the programme is to protect witnesses of human rights violations, who are usually not inclined to accept measures which radically alter their lives, such as relocation. Moreover, witnesses’ mistrust of regular security services, particularly in a post-conflict society, renders it preferable for a specialized agency to take charge of all witness protection measures. However, the law should be more explicit in providing for perpetrator-focused protection measures, including the investigation of threats, control of the activities of the accused who is not in detention, and other mechanisms to prevent and neutralize the threat, whenever possible, rather than shield the witness. 50 51 GE.10-15173 Argentina, Programa nacional de protección de personas en situación de peligro en procesos penales, No. de expediente 6526-D-2008, Tramite Parlamentario, 168 (20/11/2008). Human Rights Council resolution 12/12 (A/HRC/RES/12/12) encourages States to provide effective protection to witnesses of all human rights violations. 15