Actus reus is the act—or the omission or failure to act when there is a duty to act—that comprises the physical elements of the commission of a crime. The actus reus generally must be voluntary bodily movements that constitute a crime.
In contrast, mens rea (meaning “guilty mind”) is the criminal intent element of a crime. It is the intent to commit a crime, or the knowledge that the action, or failure to act when there is a duty to act, will result in the commission of a crime.
In New Hampshire, as in other jurisdictions, the concept of actus reus requires that a defendant must have engaged in a voluntary act, or an omission when there is a legal duty to act, that constitutes a crime. This means that involuntary actions, such as reflexive or convulsive acts, or actions taken while unconscious, are not considered actus reus. For an omission to be punishable, there must be a statutory or contractual duty to act. Mens rea, on the other hand, refers to the mental state of the defendant at the time of the crime. New Hampshire law recognizes various levels of mens rea, including purposely, knowingly, recklessly, and negligently, as defined in the New Hampshire Criminal Code (RSA 626:2). The required level of mens rea varies depending on the specific crime, but it generally involves an intention to commit the act that constitutes the crime or knowledge that one's actions are likely to result in a criminal outcome.