This warning was formed because of an American case. Here's the thing: Miranda is a young man. He was arrested by the police in Phoenix, Arizona on 1963 for kidnapping and raping a girl with mental retardation of 18 years old. After being interrogated at the police station for two hours, he signed the confession. But afterwards, he said that he didn't know that the Fifth Amendment gave him the right to remain silent. In other words, Miranda didn't know that she had the right to remain silent, or that she had the right to get the help of a lawyer, and the police didn't tell him. His lawyer protested in court that according to the constitution, Miranda's confession could not be used as evidence to confess the crime. Although the constitutional amendment has existed for nearly 200 years, until the early 1960s, American judicature has always followed the principle handed down from history: if a suspect makes a "voluntary" confession, it can be submitted to the court as evidence. It does not emphasize that the police must inform the suspect of his rights. "Willingness" rather than coercion was the only criterion at that time. Therefore, Miranda's confession was used as the main evidence of conviction in court. He was sentenced to 20 years in prison. He appealed all the way to the Federal Supreme Court on the grounds that he had "no right to know" and was reviewed by the Supreme Court.
1966, the Supreme Court presided over by Chief Justice Warren made a ruling, pointing out that citizens have the right to know their Fifth Amendment rights before being interrogated, and the police have the obligation to inform the suspects and inform them of their rights before being interrogated. Therefore, Miranda's case was declared invalid and sent back for retrial.
From now on, if the American police forget these keywords when arresting people, all the confessions made by the prisoner will be invalidated at the trial, and finally the prisoner may be released by the court because his rights were violated at the time of arrest. Starting from 1966, all police officers in the United States should tell the suspect "Miranda warning" before interrogating him, no matter how busy, hurried, unhappy and nervous the police were at that time. This is the origin of the famous "Miranda warning".
Results of retrial of Miranda case: After the Supreme Court ruled Miranda case, Miranda case was retried, jurors were re-selected and evidence was re-submitted. Miranda's confession was certainly useless. Fortunately, the prosecution found new evidence. Miranda once boasted about her criminal experience to her ex-girlfriend. The police found this girlfriend and she testified in court. Miranda was found guilty again. 1972, Miranda was released on parole. 1976, 34-year-old Miranda was stabbed to death in a bar. The police arrested a suspect in his assassination. Before the trial began, the police conveyed the "Miranda warning" to the suspect, who chose to remain silent, but the police still prosecuted him according to law.