Fine.
Please cite the Article of or Amendment to the Constitution that requires police or prosecutors to WARN suspects to not confess.
"Thus, if law enforcement officials decline to offer a Miranda warning to an individual in their custody, they may interrogate that person and act upon the knowledge gained, but may not use that person's statements to incriminate him or her in a criminal trial.
The concept of "Miranda rights" was enshrined in U.S. law following the 1966 Miranda v. Arizona Supreme Court decision
Yes you are correct, the concept of "Miranda Rights" is not part of the constitution, rather a law to protect an individual of their constitutional rights.
In my original statement i included the word "law" as part of the concept of that the administration of law must be executed with consistency.
It appears to me, that in regards to Dzhokhar Tsarnaev, the justice system is acting properly in this moment, subject to change.