My name is ***** ***** I am an experienced criminal
Yes, if you don't do as you agreed or, for that matter, if you do but don't give the police any useful information they can charge you still with the crime they arrested you for originally. The state has until the statute of limitations runs out to file charges against you. I don't know what this happened in, but in most that would give them at least 6 months to file a misdemeanor
charge and years if the charge is a felony.
If you tell me where this happened -- just the state -- I could tell you how long the police could take to have you charged.
Most non-lawyers misunderstand Miranda. Miranda violations do NOT result in the dismissal of a case. In fact, in many cases, Miranda warnings aren't even necessary.
Miranda stands only for the fact that you do not have to agree to be interrogated by the police after you've been arrested. If you are never questioned about the incident after you're arrested, Miranda warnings do not apply. If they DO apply but you weren't warned and you made damaging statements or signed a confession, then you could get a pre-trial
hearing to try to keep those statements/confession out of your trial. If the judge finds your Miranda rights
were violated, the confession and statements cannot come in to be used against you. But it doesn't result in the dismissal of the case.