Author: Aviral Umrao, Research Associate
The general basis for imposing liability in criminal law is that the defendant must be proved to have committed a guilty act whilst having had a guilty state of mind. The physical elements are collectively called as Actus reus. And the accompanied mental state is called the Mens rea. In order to commit a crime an actor must possess both Mens rea and Actus reus. That is, an act is not guilty unless the mental state by which it was commissioned is also guilty. The crime is the combination of both, and is a single unity.
Mens rea is a legal phrase used to describe the mental state a person must have been in while committing a crime for it to be intentional. It can refer to a general intent to break the law or a specific, premeditated plan to commit a particular offense. To convict an accused person of a wrong doing, a criminal prosecutor must show beyond any reasonable doubt that the suspect actively and knowingly participated in a crime that harmed another person or their property1.
To put it simply, Mens rea determines whether someone committed a criminal deed purposefully or accidentally. This idea commonly applies to murder cases. The perpetrators’ Mens rea, or mental state at the time of the killing, is an essential factor in whether they will be declared guilty or innocent. In order to receive a conviction, the lawyer must prove that the accused party had some intention or willingness to end the life of another person. On the other hand, if evidence shows the death to be accidental and unavoidable, the suspect must be declared innocent and set free2.
The law did not always require Mens rea for liability. Early Germanic tribes, it is suggested, imposed liability upon the causing of an injury, without regard to culpability. But this was during a period before tort law and criminal law divided. It seems likely that as the distinction between tort and crime appeared that is, as the function of compensating victims became distinguished from the function of imposing punishment, the requirement of Mens rea took on increasing importance.
The phrase “Mens rea” appears in the Leges Henrici description of perjury — reum non facit nisi Mens rea — which was taken from a sermon by St. Augustine concerning that crime. The sermon is also thought to be the source of the similar maxim in Coke’s Third Institutes, the first major study of English Criminal law: “actus non facit reum nisi mens sit rea” [the act is not guilty unless the mind is guilty]3.
Once adopted as a basic principle of criminal law, the legal meaning of Mens rea continued to evolve. The early stages of its development are illustrated by the decision in Regina v. Prince4. The defendant took an underage girl “out of the possession” of her father, reasonably believing she was over the age of consent. That the defendant’s conduct was generally immoral was sufficient for Lord Bramwell to find that the defendant had the Mens rea necessary for criminal liability. Lord Brett, on the other hand, would require that Prince at least have intended to do something that was criminal, not just immoral.
A somewhat more demanding requirement is expressed in Regina v. Faulkner5. In the process of stealing rum from the hold of a ship, a sailor named Faulkner accidentally set the ship afire, destroying it. Building upon Lord Brett’s conception of a more specific and demanding Mens rea, Lords Fitzgerald and Palles conclude that the Mens rea requirement means that Faulkner must have at least intended to do something criminal that might reasonably have been expected to have led to the actual harm for which he is charged. Thus, Faulkner ought not be liable for the offense of burning a ship when he intended only to steal rum from it; such conduct, in the normal course of things, does not lead one to reasonably foresee that a ship will be destroyed.
This last shift in the notion of Mens rea marks not only a dramatic increase in the demand of the requirement, but also a significant qualitative change. No longer does there exist a single Mens rea requirement for all offenses the intention to do something immoral or, later, something criminal. Now each offense has a different Mens rea requirement, the Mens rea required for the offense of burning a ship is different from the Mens rea required for the offense of theft. Liability now requires that a person intend to do something that might reasonably be expected to lead to the harm of the particular offense charged. As some have expressed it, there is no longer a Mens rea for criminal liability but rather mentes reae.
Actus reus is the Latin term used to describe a criminal act. 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 others6.
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 fact7.
As far as criminal law is concerned, there are five instances under which a failure to act may result in criminal prosecution.
- If the defendant has a special relationship to the victim, he may have a duty to act in certain situations. The special relationships that establish the duty to act are parent/child relationships, husband/wife relationships and employer/employee relationships.
- There are statutory duties to act. In other words, certain states have passed statutes requiring a person to act and failure to do so will result in criminal prosecution.
- A private contract between two parties can generate a duty to act. This is usually the case in situations where the defendant was under a contractual duty to protect or care for someone else8.
- Where the failure to act can result in criminal prosecution is where the defendant had no legal obligation to aid the victim but he voluntarily undertook to aid the victim. In this situation, if the defendant abandons his rescue efforts and thereby leaves the victim in a condition that was worse than he would have been in had the defendant not started to help at all, the defendant can be criminally liable.
- Where a defendant will have the duty to aid another person if he wrongfully placed the victim in harm’s way to begin with. In this situation, failure to help the victim can result in criminal liability. For better or for worse, the law still does not impose criminal liability for an omission to act where the defendant had nothing more than a moral duty to act9.
Coincidence of actus reaus and Mens rea:
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]10. Where an offence requires Mens rea the prosecution must prove that the accused had Mens rea at the time he did the act which caused the actus reaus11. It is a general principle in criminal law that for a person’s liability to be established it must be shown that the defendant possessed the necessary Mens rea at the time the Actus reus was committed in other words the two must coincide12. This is also known as the contemporaneity rule. In some cases a literal interpretation of this rule would manifestly lead to injustice, and the courts have developed ways of finding coincidence of Mens rea and Actus reus (a) when the events take place over a period of time13, and (b) where they constitute a course of events14.
- ASHWORTH, ANDREW. Principles of Criminal Law. 2 ed. Oxford: Clarendon Law Series, 1995. [↩]
- OP Srivastava’s Principles of Criminal Law, EBC, fifth edition, 2010. [↩]
- Paul H. Robinson, 8346 words, August 19, 1999, University of Pennsylvania Law School, Penn Law [↩]
- L.R. 2 Cr. Case. Res. 154 (1875). [↩]
- 13 Cox CC 550 (1877). [↩]
- State v. Mercer, 165 S.E.2d 328 (N.C. 1969). [↩]
- People v. Beardsley 113 N.W. 1128 (Mich. 1907). [↩]
- Commonwealth vs. Pestinikas, 617 A.2d 1339 (Pa. 1992). [↩]
- People v. Beardsley 113 N.W. 1128 (Mich. 1907). [↩]
- R v Church  1 QB 59 [↩]
- Jakeman (1982) 76 Cr App R 223 [↩]
- Fagan v MPC  1 QB 439 [↩]
- Kaitamaki v R  AC 147. [↩]
- Thabo Meli v R  1 WLR 228 [↩]