Guidelines on international standards I. The origins of the obligation to investigate ill-treatment 1.1 The absolute prohibition of ill-treatment 1.1.1 The use of torture or inhuman or degrading treatment or punishment is absolutely prohibited in all circumstances. No derogation from this prohibition is permissible. 1.2 The obligation to investigate ill-treatment 1.2.1 Without a positive obligation to investigate allegations or other indications of ill-treatment, the prohibition would be rendered theoretical and illusory, thus allowing state authorities and their agents to act with impunity. The duty to investigate serious (deliberate) ill-treatment as well as other serious human rights violations has an absolute character. 1.2.2 The obligation to investigate demands a coherent system of measures capable of ensuring an adequate response to credible accounts of torture and other forms of ill-treatment. It requires that states maintain mechanisms and procedures through which investigations can be initiated and that they adequately punish the perpetrators of ill-treatment. 1.2.3 State authorities must discharge the investigative duties in a manner consistent with their obligation to combat impunity for ill-treatment and other serious human rights violations. 1.2.4 States are to combat impunity, which arises where those responsible are not brought to account, as a matter of justice for the victims, as a deterrent with respect to future human rights violations and in order to uphold the rule of law and public trust in the justice system. ► Page 9