Many times, aside from strict liability crimes, the converse is also true: A guilty act alone is not enough for criminal liability – one must concurrently have a guilty mind. A guilty mind is called by lawyers the mens rea portion of a criminal offense. An old Latin maxim says, “actus not facit reum nisi mens sit rea,” which means that an act does not make one guilty unless his or her mind is guilty.

The actus reus and mens rea must always be concurrent in order for criminal liability to attach. If one commits an actus reus one day and later has the requisite mens rea the next day, there can be no criminal liability.

For example, if someone borrows his neighbor’s lawnmower one day with the intent to return it the next day, but rather than return the mower the next day he instead decides to keep the mower for himself, the common law crime of larceny is not met. This is because the actor did not have the guilty mind at the time of the taking and carrying away of his neighbor’s mower.

This does not mean that the law will do nothing about the wrongful taking of a neighbor’s mower, however. The above example simply demonstrates that the crime of larceny may not be met if the actus reus and mens rea are not concurrent. Civil law does not have this particular, unique classification of the guilty mind and the guilty act. Trespass to chattel (e.g. taking a mower without permission) would not require the element of a guilty mind for civil liability to attach.

The Model Penal Code uses only four main categories for the mens rea requirement. They are:

1) intentionally or purposefully,
2) knowingly,
3) recklessness, and
4) criminal negligence.

California applies its own statutory and case law in regards to the element of criminal intent. If you require the assistance of a criminal defense lawyer, please feel free to contact an attorney in our Orange County office for further assistance.