Mens Rea

There are only two states of mind which constitute mens rea, according to Black's Law Dictionary at p.1076 9th ed., citing J. W. Cecil Turner: KENNYs OUTLINE OF CRIMINAL LAW 29 – 30 (6th Ed. 1952). They are the intention, and recklessness with which the accused proceeded in the act said to be criminal.

It is a fundament principle of criminal law that a crime consists of both a mental and a physical element. Mens rea, a person's awareness that his or her conduct is criminal, is the mental element, and actus reus, the act itself is the physical element. The concept of mens rea, which is Law Latin for "guilty mind", developed in England around the year 1600, when Judges began to hold that an act alone could not create criminal liability unless it was accompanied by a guilty state of mind. The degree of mens rea required for a particular common law crime varied then'
In other words, mens rea is a criminal intention or knowledge that an act is wrong, and today most of the crimes are defined by statutes that generally contains a word or phrase indicating the mens rea requirement. Thus, a typical statute may require that a person act knowingly, purposely or recklessly – see legal-dictionary.thefreedictionary.com. In this case, the Appellant was charged with the offence of murder contrary to Section 316 of the Criminal Code applicable in Ondo State, and the Prosecution was expected to prove beyond reasonable doubt that the alleged act was intentional with the knowledge that death or grievous bodily harm was a probable consequence – Akinfe V. State (1988) 3 NWLR (Pt. 85) 729.

The elements of this offence thus reveal that there is not just the requirement for the actus reus to have been committed but the accused person must also demonstrate an intention to defraud, the mens rea must be established. The standard common law test of criminal liability is expressed in the Latin phrase actus reus non facit reum nisi mens sit rea, meaning: "the act is not culpable unless the mind is guilty". It is a fundamental principle of criminal law that a crime consists of both a mental and a physical element. Mens rea, a person's awareness of the fact that his or her conduct is criminal, is the mental element, and actus reus, the act itself, is the physical element; West's Encyclopedia of American Law, edition 2. Copyright 2008. These two requirements were succinctly described by Tobi, JSC in Abeke v The State (2007) LPELR-31(SC) at page 18 of the E-Report in these terms: Mens rea means a guilty mind. And actus reus means a guilty act. Put in another language, the guilty mind instigates the guilty act or flows into the guilty act.
See also Mohammed v The State (1991) LPELR-1901(SC); Eyo v The State (2017) LPELR-43332(CA). Mens rea revolves on the intent of the accused person. If the accused person intended his action and proceeds to carry it out, then the mens rea and actus reus have been proved. Except it is a strict liability offence, if the prosecution is unable to prove the mens rea of the accused person in a criminal trial, notwithstanding the actus reus, the accused person may escape conviction as the offence would not have been proved.