The Peter Donovan case led to a famous lawsuit, because he was questioned for three days by the police before he was allowed to see an attorney. The robbery happened in 1961 and he was executed in 1963 or 1964. Pete’s case was one of the events that contributed to the Miranda Rights ruling in 1966.(Page 23 - Kindle version)
The Miranda warning came into the practice of the USA law enforcement system after the case regarding Ernesto Miranda in 1963. In short, it allows the suspect to get legal aid from a lawyer when he faces questioning by the police, and he/she gets the right to remain silent and the interview will be over if he/she decides to remain silent. Please follow the below link from Wikipidea for further details.
https://en.m.wikipedia.org/wiki/Miranda_v._Arizona
This practice was included with the intention of protecting the innocent suspects from the questionings by the police which can sometimes be unjust as well as barbaric (a popular secret). It may have its pros like preventing the innocent from being brutally treated, protect them from taking wrong confessions which are made under threats and the wrong party being punished in court cases. But I think this is used more frequently by the professional criminals to just manipulate the police and their interrogations, and they know that police can do nothing more than just questioning. And the lawyer who will present at the time of interrogation will support this not with the best interest of the police, but of his client. By this way I think the criminals are mostly benefited by this rather than the innocent. What do you think?
– William James