Torture is one of the most serious violations of human rights and is one of the ultimate acts of violence and "perversion" of one human being over another. It transcends not only the individual sphere, since it reaches all the vital spheres of those involved. The United Nations published the "Istanbul Protocol", which is the international instrument par excellence for documenting torture and its consequences, as it sets out the general principles to be followed, the obligations of states to prevent, investigate and punish it, as well as the minimum elements that must be included in expert opinions. The Stabul Protocol highlights the central role of psychological assessment in an investigation of torture.