Actus reus and mens rea are two of the five elements of a crime that the prosecution may have to prove to get a conviction in a criminal case. Actus reus is the criminal act. Mens rea is the intent to commit the crime. In general, the more serious a crime is, the more important it is for the prosecution to prove that both a criminal act was committed and that there was criminal intent. These more serious crimes are also known as conduct crimes. Not surprisingly, conduct crimes involve the proof of criminal conduct. Criminal conduct is often confused with criminal acts. The distinction is that criminal conduct involves both actus reus and mens rea, whereas a criminal act only involves actus reus. In the most severe of crimes, such as criminal homicide, three more elements of crime must be proven: concurrence, attendant circumstances and a bad result. Actus reus and mens rea are important because both elements are necessary to get a conviction beyond a reasonable doubt in a criminal case (Samaha, 2008, chap. 3).
In order to qualify as actus reus, the act must be deemed a bodily movement that was voluntary. The reason for this is that the law is intended to punish people who meant to commit the act or can be blamed for the act. Only then are they responsible for the criminal acts they commit. Criminal law does not intend to punish people who are not responsible for the acts they committed. The problem is that most criminal codes provide vague descriptions of what a voluntary act is. Many times, the definition needs to be inferred by looking at the list of exceptions (involuntary acts) to voluntary acts. An appeal in case of Brown v. State centered around whether the jury should be given specific instructions by the judge on how to ascertain whether an act was voluntary. The defendant in that case, Alfred Brown, was bumped with a moholding was that the defendant was entitled to have the jury consider the voluntariness of his
References: Did she have a legal duty to report or intervene? Retrieved from http://www.soc.umn.edu/~samaha/cases/state_v_kuntz_omission.htm. Miller, C. (2009, January 14). Calif. lawmakers rush to rescue good samaritans in wake of court ruling. The Recorder. Retrieved from http://www.law.com/jsp/article.jsp?id=1202427434865&slreturn=1&hbxlogin=1. Samaha, J. (2008). Criminal Law. (9th ed., chap. 3-4). Belmont, CA: Thomson Learning, Inc.