In Illinois v. Perkins, the U.S. Supreme Court rules that the Fifth Amendment’s self-incrimination clause is not violated where a suspect in custody confesses to an undercover police officer posing as a fellow inmate. The Court rules that even though a police officer was doing the questioning, and even though he did not give a Miranda warning to the suspect, no Fifth Amendment violation occurred because the “essential ingredients of a ‘police-dominated atmosphere’ and compulsion are not present when an incarcerated person speaks freely to someone that he believes to be a fellow inmate.”