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:
- Purposely - Express purpose to commit a specific crime against a particular person
- Knowingly - Knowledge that one's actions would certainly result in a crime against someone, but did not specifically intend to commit that crime against the particular victim which one is accused of injuring
- Recklessly - Knew that one's actions had an unjustifiable risk of leading to a certain result, but did not care about that risk ("reckless disregard"), and acted anyway
- Negligently - Did not intend to cause the result that happened, but failed to exercise a reasonable duty of care to prevent that result (which includes failing to become aware of the risk of that result)
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.