Mens rea is a Latin term meaning "guilty mind". It refers to the criminal intent that is necessary as an element to be proven in a crime. Many civil law claims also include some level of mens rea as a required element.
The four levels of mens rea set forth in the Model Penal Code are:
Young children are presumed incapable of criminal intent (incompetent) and may not be criminally prosecuted. The states without a statutory minimum age for prosecution determine the jurisdiction of the court based on case law and circumstances demonstrating the child's competence, or lack thereof. Most states specify that prior to age six or seven, juveniles are incomptent and cannot form criminal intent.