Criminal Law
AK-tus REE-usActus Reus
Definition
Actus reus ("guilty act") is the physical or external component of a crime. It requires a voluntary act or, in limited circumstances, an omission to act when there is a legal duty to do so. Involuntary acts — such as reflexes, convulsions, or conduct during unconsciousness — do not satisfy the actus reus requirement. The actus reus must coincide in time with the mens rea. An omission can constitute actus reus when there is a statutory duty, contractual duty, special relationship, or voluntary assumption of care.
Example
A bystander watches a stranger drown and does nothing. Unless there is a legal duty to act (such as a lifeguard's contractual duty), the bystander's inaction does not constitute actus reus.