Actus Reus

In determining whether a person committed a crime, there are two issues to consider: the person’s state of mind, or intent, and the actual physical act of committing the crime. The Latin term actus reus refers to the actual act of doing the illegal thing, with no reference to the person’s mental state. In order for a person to be convicted of having committed a crime, it must be proven that he engaged in some physical act, or took action, to do so. To explore this concept, consider the following actus reus definition.

Definition of Actus Reus


ack-tus  ree-us


  1. An actual action that is a fundamental component of a crime, as compared with the perpetrator’s state of mind or intent.



What is Actus Reus

In the legal system, the question of whether a crime has been committed is generally decided by pairing whether an actual act or omission took place, with the mental state of the accused. These individual elements, actus reus, and mens rea, make up what are referred to as “constituent elements,” or component parts, of a crime, and in almost all cases, both must be present.

The legal term actus reus, as used in modern times, stems from the 16th century writings of Sir Edward Coke, in which he stated actus non facit reum nisi mens sit rea, which means “an act does not make a person guilty unless [his] mind is also guilty.” This concept is the basis of today’s legal test of guilt, which requires proof of fault, or culpability, in both thought and deed.

Examples of Actus Reus

In almost every crime it is necessary for the prosecution to prove that some action of the defendant’s resulted in the effect, which is a criminal act.

Lack of Intent or Physical Act

Mark was the victim of fraud, and Bill has been accused of the crime. Leading up to the incident at hand, Bill had sold his car to a man who paid him with a check. Bill deposited the check, then turned around and hired Mark to repair the plumbing in his bathroom, paying him with a personal check. A day after Mark had deposited Bill’s check, it bounced, causing a number of his own payments to bounce, resulting in a whole slew of bank fees.

When Mark asked Bill to pay him in cash, and to pay all of his bounced check fees, Bill was simply unable to do so. He was a victim himself of the man who defrauded him out of his car. Mark takes the bounced check to the District Attorney (“DA”), who considers whether criminal charges should be pressed, but Mark is disappointed when he declines to do so. The DA explains that, while there is no doubt that fraud, and a financial debacle have occurred, there is no proof that Bill intended (mens rea) to bilk Mark out of his hard-earned money, nor did any actual action taken by Bill (actus reus) amount to a crime.

Although Mark has the right to demand payment from Bill, and can file a civil lawsuit if necessary, this example of actus reus means that only the man who originally defrauded Bill out of his car, actually acted in an illegal manner.

The Question of Action vs. Being

In 1962, the U.S. Supreme Court addressed the issue of actus reus as it reviewed California’s drug law which stated:

“No person shall use, or be under the influence of, or be addicted to the use of narcotics, excepting when administered by or under the direction of a person licensed by the State to prescribe and administer narcotics.”

The case stemmed from the arrest of a man based on the police officer’s observation of “tracks” on his arm from heroin use. Based on the officer’s statement that the man had admitted to being a drug addict, the man was charged and convicted under the law, and sentenced to 90 days in jail.

In this case, Robinson v. California, 370 U.S. 660 (1962), the Court ruled that California’s law making it illegal to be a drug addict was unconstitutional, because the status of being something is not an act, and therefore not criminal. This example of actus reus being a necessary component part of a crime would require certain circumstances to exist in order to convict this man.

First, the man would have to be charged with the act of consuming the drugs, whether by injection, orally, inhalation, or otherwise, and that action would have to be proven. The second element is intent, or mens rea. This would come into play if a person was under the influence of some drug that someone else forced on him, such as a date rape drug, or other illegal substance.

Related Legal Terms and Issues

  • Civil Lawsuit – A lawsuit brought about in court when one person claims to have suffered a loss due to the actions of another person.
  • District Attorney – An attorney employed by a county or other district, charged with prosecution of criminal charges on behalf of the government. Also: Prosecutor.
  • Intent – A resolve to perform an act for a specific purpose; a resolution to use a particular means to a specific end.
  • Mens Rea – The intent to do wrong that constitutes part of a crime, as compared to the actual act or conduct of the accused.