If the police didn't read me my rights, can my case be dismissed?
Two factors will generally determine whether you can get a case dismissed for the failure of the police to read you your rights, otherwise known as giving you Miranda warnings: Whether you were in custody at the time of the questioning; and whether there is other evidence against you.
Miranda warnings refer to a set of warnings advising a person that they have the right to remain silent and to have an attorney during questioning, and that any statements they make can be used against them in court. Most people think that the police have to read Miranda warnings every time they talk to a defendant. However, the police are only required to read Miranda warnings before custodial interrogations.
Custodial interrogation means that the individual is in jail or in custody, or otherwise not free to leave, and the police are asking them questions about a crime. If they are not under arrest or in custody, the police are not required to read them Miranda warnings.
If a person is in custody or jail and the police asked them questions without reading their rights, any statements they make are obtained illegally. If the individual or their attorney files a motion to suppress, the illegally-obtained statements should be thrown out. Keep in mind, though, that only the statement gets thrown out. The case may or may not be dismissed depending on the other evidence available. For example, if a person confessed to assaulting someone and the statement was thrown out, the state may still continue with the prosecution if they have other evidence, like an eye-witness. If the only evidence against a person is a confession, and it is thrown out because the police didn't give Miranda warnings, then the case will very likely be dismissed.
Miranda warnings stem from Supreme Court rulings, either through statutes or interpretations by courts. Some states actually provide even more protections and rights. The best defense to illegal questioning, though, is silence and a good attorney. Many people will attend interviews and answer questions in a vain attempt to cooperate, thinking they are helping their case. Unfortunately, they end up creating more headaches for themselves and their attorneys who try to defend them later on. If you think that you were tricked into giving a confession, you should consult with an attorney as soon as possible to see what rights are available to you in your jurisdiction.