Outlawing all forms of ill-treatment can only be achieved by effective investigation and prosecution of the offenders. This chapter considers the duty to investigate both torture and other cruel, inhuman, and degrading treatment or punishment. Where any ill-treatment is credibly alleged, a State is obligated by treaty and/or customary law to investigate. Where criminal wrongdoing amounting to torture or other ill-treatment is identified in the course of an impartial investigation, the perpetrators must be prosecuted and, if convicted at the end of a fair trial, duly punished. In practice, even when the crime is on the statute book in any given domestic legal regime and the various elements of the offence pertain to any individual, it is very rare for the specific charge of torture to be laid. More often, when a prosecution is mounted, for instance against a police officer or other law enforcement official alleged to have ill-treated a suspect, detainee, or other person, assault—not torture—is the charge on which the accused is indicted.