Actus Reus: Cases & Elements

Instructor: Kenneth Poortvliet

Kenneth has a JD, practiced law for over 10 years, and has taught criminal justice courses as a full-time instructor.

To convict someone of a crime, they must have committed a voluntary act. In this lesson, we will learn what actus reus is and examine its role in the prosecution of every crime.

The Criminal Act

Sleepwalker Cindy got up and poured lighter fluid on her couch. She then lit it on fire and went back to bed. A few minutes later she woke to the sound of her fire alarm. In a panic, she rounded up her three kids and fled the house. A month later, she stood before a magistrate and pleaded not guilty to arson charges.

Most crimes have statutory elements, which are facts and conditions that are expressed in the written law and need to be proven by a prosecutor to convict someone of a crime. In addition, the law has traditionally required general elements of every crime that are external to the penal code but are just as necessary to prove. The general elements that deal with the criminal act are:

  • Actus Reus: Latin for ''guilty act''; is the voluntary act that is at the heart of a crime.
  • Mens Rea : Latin for ''guilty mind''; is the guilty or evil state of mind that, when existing concurrently with the actus reus, creates criminal liability for the defendant. Also known as intent.

These elements have to be concurrent, meaning both are present at the moment of the crime. The guilty mind has to exist for the act that kills or harms. It works like this: Peter wants to kill Paul and pushes him over the boat into the sea, and Paul dies. The guilty act and the guilty mind operate together to commit the crime of murder. However, let's say Peter wants to kill Paul and plans to push him into the sea, but before he does, they hook a big fish and Peter pulls on the net, which accidently sends Paul into the water, killing him. Peter wanted to kill Paul and his act of pulling on the net sent him into the water, but pulling on the net was to get the fish in, not kill Paul, so there is no concurrence of act and intent.

Actus Reus

It's often said that actus reus is the physical element of a crime while mens rea is the mental element. This it true when the circumstances of the crime cooperate. Person A wants to kill person B; A shoots B, B dies. In concert we can see how the actus reus, in this case the shooting, was a requisite condition of the crime. But what is it about the nature of the act that makes it a crime? Courts have often referred to the actus reus element as the ''voluntary'' act. The idea is that if the act in question was not voluntary at it's inception, then it's not a crime.

For example, Bob's showing Leo his new knife, and in a fit of epilepsy, he plunges the knife through Leo's heart. The act is involuntary, and thus we would probably not hold Bob criminally liable. In State v. Mercer NC (1969), the North Carolina Supreme Court said, ''The absence of consciousness not only precludes the existence of any specific mental state, but also excludes the possibility of a voluntary act without which there can be no criminal liability.'' In this case, Mercer admitted he shot his wife and two kids, but was in an unconscious state. The state's supreme court ordered a new trial because the trial judge failed to instruct the jury that they could acquit if they felt Mercer's act was not a voluntary act.

Inaction As An Act

Omission as an act occurs when someone has a duty to act but doesn't. In R v. Dytham (1979), an on-duty police officer standing 30 yards from a nightclub door watched a man get tossed out and then beaten to death while he watched. At trial, he said he didn't want the paperwork because his shift was about to end. His conviction shows that a voluntary omission in the face of a duty will equal the actus reus of a crime. The court upheld his conviction as he had a lawful duty to act, but didn't. However, if a regular Joe was walking by and did nothing, there would be no crime.

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