27. An investigation must be carried out diligently and in accordance with good practice.63 The investigative mechanism charged with conducting the investigation must be adequately empowered to do so. The mechanism must, at a minimum, have the legal power to compel witnesses and require the production of evidence,64 and must have sufficient financial and human resources, including qualified investigators and relevant experts.65 Any investigative mechanism must also be able to ensure the safety and security of witnesses, including, where necessary, through an effective witness protection programme. iii. Independent and impartial 28. Investigators and investigative mechanisms must be, and must be seen to be, independent of undue influence. They must be independent institutionally and formally, as well as in practice and perception, at all stages. Investigations must be independent of any suspected perpetrators and the units, institutions or agencies to which they belong. Investigations of law enforcement killings, for example, must be capable of being carried out free from undue influence that may arise from institutional hierarchies and chains of command. Inquiries into serious human rights violations, such as extrajudicial executions and torture, must be conducted under the jurisdiction of ordinary civilian courts. Investigations must also be free from undue external influence, such as the interests of political parties or powerful social groups. 29. Independence requires more than not acting on the instructions of an actor seeking to influence an investigation inappropriately. It means that the investigation’s decisions shall not be unduly altered by the presumed or known wishes of any party. 8 30. Investigators must be able to perform all of their professional functions without intimidation, hindrance, harassment or improper interference, and must be able to operate free from the threat of prosecution or other sanctions for any action taken in accordance with recognized professional duties, standards and ethics. This applies equally to lawyers, whatever their relationship to the investigation.66 31. Investigators must be impartial and must act at all times without bias. They must analyse all evidence objectively. They must consider and appropriately pursue exculpatory as well as inculpatory evidence. iv. Transparent 32. Investigative processes and outcomes must be transparent, including through openness to the scrutiny of the general public67 and of victims’ families. Transparency promotes the rule of law and public accountability, and enables the efficacy of investigations to be monitored externally. It also enables the victims, defined broadly, to take part in the investigation.68 States should adopt explicit policies regarding the transparency of investigations. States should, at a minimum, be transparent about the existence of an investigation, the procedures to be followed in an investigation, and an investigation’s findings, including their factual and legal basis. 33. Any limitations on transparency must be strictly necessary for a legitimate purpose, such as protecting the privacy and safety of affected individuals,69 ensuring the integrity of ongoing investigations, or securing sensitive information about intelligence sources or military or police operations. In no circumstances may a state restrict transparency in a way that would conceal the fate or whereabouts of any victim of an enforced disappearance or unlawful killing, or would result in impunity for those responsible. 63 See, e.g., Human Rights Committee, Abubakar Amirov and others v. Russia, paras. 11.4 ff.; IACtHR, Rodríguez Vera and others (The Disappeared from the Palace of Justice) v. Colombia, Judgment, 14 November 2014, para. 489. 64 ECtHR, Paul and Audrey Edwards v. UK, Judgment, 14 March 2002. 65 IACtHR, “Mapiripán Massacre” v. Colombia, Judgment, 15 September 2005, para. 224. 66 UN Basic Principles on the Role of Lawyers, Principles 16 and 17. 67 A victim’s immediate family “must be involved in the procedure to the extent necessary to safeguard his or her legitimate interests”. UN Special Rapporteur on extrajudicial, summary or arbitrary executions, Interim Report, UN doc. A/65/321, 23 August 2010; ECtHR, Hugh Jordan v. UK, Judgment, 4 May 2001, para. 109. See also ACHPR, General Comment No. 3 on the Right to Life, para. 7. 68 See ICPED, Arts. 12 and 24. 69 Under Art. 137 of 1949 Geneva Convention IV, information concerning a protected person, including about his/her death, may be withheld by the Information Bureau if transmission is “detrimental” to the relatives. The Minnesota Protocol on the Investigation of Potentially Unlawful Death (2016)