74. Where the outcome of an investigation establishes the responsibility of the perpe- trators of an attack against a human rights defender, the state has a duty to bring those responsible to justice, regardless of whether those responsible are public officials or non-state actors.102 As the UN Committee against Torture has pointed out in relation to states’ obligation to take effective measures to prevent torture, it is essential to investigate and establish the responsibility not only of the direct perpetrators, but also of persons in the chain of command.103 75. The fact that violations have been committed by a subordinate does not exempt the subordinate’s superior from responsibility, in particular where criminal responsibility is established, if the superior knew or had at the time reason to know that the subordinate was committing or about to commit such a crime and did not take all necessary measures to prevent or punish the crime. As regards the responsibility of the subordinate, the fact that the perpetrator acted on orders of his or her government or of a superior does not exempt him or her from responsibility.104 A subordinate who refuses to carry out an unlawful order, however, shall not face criminal or disciplinary sanctions.105 76. Any public officials who have been found by a competent authority to be responsible for serious human rights violations or for furthering or tolerating impunity must be removed from office or subjected to other appropriate disciplinary procedures.106 Where relevant, such procedures must be accompanied by criminal prosecution107 and sentencing, which should be effective, proportionate and appropriate to the offence committed.108 Among other things, this means that the sentences should show that such acts are not tolerated and should have a sufficient dissuasive effect. 77. Given the important role of human rights work in a democratic society and the fact that threats and violence against human rights defenders on account of their human rights work often seeks to instil fear not only in the immediate victim but 102  See, for example, UN Human Rights Committee General Comment No. 31, “The Nature of the General Legal Obligation Imposed on States Parties to the Covenant”, UN Doc. CCPR/C/21/Rev.1/Add.13, 26 May 2004, para. 18. 103  See UN Committee against Torture, General Comment No. 2, “Implementation of Article 2 by States Parties”, UN Doc. CAT/C/GC/2, 24 January 2008, para. 9. 104  The following of orders or instructions may, however, have a bearing on the sentencing of the subordinate. See “Updated Set of principles for the protection and promotion of human rights through action to combat impunity”, UN Doc. E/CN.4/2005/102/Add.1, 8 February 2005, principle 27. See also “Guidelines of the Committee of Ministers of the Council of Europe on eradicating impunity for serious human rights violations, section XIII. Accountability of subordinates. See also “Basic Principles on the Use of Force and Firearms by Law Enforcement Officials”, Adopted by the Eighth United Nations Congress on the Prevention of Crime and the Treatment of Offenders, Havana, Cuba, 27 August to 7 September 1990, principles 24 and 26. 105  See “Basic Principles on the Use of Force and Firearms by Law Enforcement Officials”, principle 25. 106  See “Guidelines of the Committee of Ministers of the Council of Europe on eradicating impunity for serious human rights violations”, section III. General measures for the prevention of impunity, para. 7. 107  The requirements for an investigation to be effective also apply at the prosecution stage. Ibid. section VIII. Prosecutions. 108  Ibid. section X. Sentencing. 48 Guidelines on the Protection of Human Rights Defenders