Actus reus is the Latin term used to describe a criminal act. Every crime must be considered in two parts-the physical act of the crime (actus reus) and the mental intent to do the crime (mens rea). To establish actus reus, a lawyer must prove that the accused party was responsible for a deed prohibited by criminal law.
Actus reus is commonly defined as a criminal act that was the result of voluntary bodily movement. This describes a physical activity that harms another person or damages property. Anything from a physical assault or murder to the destruction of public property would qualify as an actus reus.
Omission, as an act of criminal negligence, is another form of actus reus. It lies on the opposite side of the spectrum from assault or murder and involves not taking an action that would have prevented injury to another person. An omission could be failing to warn others that you’ve created a dangerous situation, not feeding an infant who has been left in your care, or not completing a work related task properly which resulted in an accident. In all of these cases, the perpetrator’s failure to complete a necessary activity caused harm to others.
The exception to actus reus is when the criminal actions are involuntary. This includes acts that occur as a result of a spasm or convulsion, any movement made while a person is asleep or unconscious, or activities participated in while an individual is under a hypnotic trance. In these scenarios a criminal deed may be done, but it is not intentional and the responsible person will not even know about it until after the fact.