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 Indiana, 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 the physical elements of a crime. This means that for a person to be held liable for a criminal offense, there must be evidence of their actual conduct that breached the law. This could include any action, conduct, or behavior that is prohibited by law. On the other hand, mens rea refers to the mental state of the defendant at the time of the crime. It involves an individual's intent or knowledge regarding the criminality of their actions. Indiana law recognizes various levels of mens rea, from intentional and knowing to reckless and negligent conduct, depending on the specific crime. Both actus reus and mens rea are critical components in establishing criminal liability under Indiana law, and a person typically cannot be convicted of a crime unless both elements are proven beyond a reasonable doubt.