Can police question a 12 year old without a parent present and charge them with aggravated assault?

If a minor is in custody for the alleged commission of an offense that would be a crime if committed by an adult, any statement given by a minor in response to questions asked by a police officer is inadmissible unless the police officer informed the minor of the minor's rights before questioning begins.

If the child is under 14 years of age, the child is presumed not adequately mature and experienced to knowingly and voluntarily waive or understand a child’s rights unless a parent, guardian, or legal custodian is present during waiver.

If the minor is 14 years of age or older, the minor is presumed capable of knowingly and voluntarily waiving the minor's rights without the benefit of having a parent, guardian, or legal custodian present during questioning.

The presumptions outlined in paragraphs (1) and (2) may be overcome by a preponderance of the evidence showing the ability or inability of a minor to comprehend and waive the minor's rights.

            Usually, when a person states, “I was not read my rights!” they are referring to their Miranda Warnings/Rights. Miranda Warnings protect people from being compelled in any criminal case to be a witness against themselves.[1] The Miranda Warnings/Rights are: (1) You have the right to remain silent; (2) Anything you say can and will be used against you in court; (3) You have the right to consult with an attorney and have an attorney present during questioning; and (4) If you cannot afford an attorney, one will be provided to you before questioning at no cost to you.[2]   

   However, many people misunderstand when a peace officer is required to give them Miranda Warnings.  A suspect is only accorded Miranda protections during a custodial interrogation.  Both elements (i.e., custody and interrogation) must be present before the peace officer is required to give Miranda Warnings.  That means peace officers are not required to give Miranda Warnings when they are still in the investigatory stage.  For instance, a peace officer is not required to give Miranda Warnings when he asks a person suspected of driving under the influence if they have been drinking or asks them to conduct field sobriety tests.  This is because the peace officer is still trying to ascertain whether a crime has been committed (i.e., The Investigatory Stage).

            That said, in Utah, a person is in custody when an individual’s freedom of action is curtailed to a degree associated with a formal arrest.  The inquiry is objective, and a person may understand himself to be in custody based either on physical evidence or on the nature of the peace officer’s instructions and questions.  Utah Courts have set out a five-factor test to determine when a person is in custody for the purpose of Miranda protections. They are: (1) the site of the interrogation; (2) whether the investigation focused on the accused; (3) whether the objective indicia of arrest were present; (4) the length and form of the interrogation; and (5) whether the accused came to the place of interrogation freely and willingly.

Hope this helps