CHAPTER ONE: GENERAL INTRODUCTION
1.1. Background of the Study
Crime may be defined as an act, default or conduct prejudicial to the community, the commission of which by law renders the person responsible liable to punishment by fine or imprisonment in a special proceeding. Crime can also be viewed as an act or omission which is rendered punishable by some legislative enactment. It is simply an act in violation of the penal laws of a state. In encapsulation, crime is an act inconsistent with the norms acceptable in any society. The general characteristic of crime is that it affects the community as a whole, as distinct from evil wrong. If the definition of any particular offence is thoroughly scrutinized, it will be deciphered that it nearly always consists of two sorts of elements – physical and mental. Succinctly, mensrea refers to the mental element of the offence that accompanies the actusreus. In some jurisdictions the terms mensrea and actusreus have been superseded by alternative terminology. In Australia, for example, the elements of all federal offences are now designated as “fault element” and “physical element.” This terminology was adopted in order to replace the obscurity of the latin terms with simple and accurate phrasing. Every crime is a violation of law but it is not every violation of the law that counts as a crime.
It is also pertinent to point out that it is not every crime that is an international crime. In Re List &ors the United States Military Tribunal at Nuremberg defined international crime thus:
An International Crime is such act universally recognized as criminal, which is considered a grave matter of international concern and for some valid reason cannot be left within the exclusive jurisdiction of the state that would have control over it under ordinary circumstances.
Consequently, it is the international community of nations that determines which crime falls within this definition in the light of the latest developments in law, morality and the sense of criminal justice at the relevant time. It is apt to contend that what acts should be characterized as international crime depends on the machinery by which such acts are to be dealt with. 
Generally, the terms actusreusandmensrea as developed in English law, are derived from principle stated by Edward Coke, namely, actus non facitreum nisi mens sit rea which means that “an act does not make a person guilty unless the mind is also guilty”. Hence the general test of guilt is one that requires proof of fault, culpability or blameworthiness both in behaviour and mind. Lord Halsham L. C. pointed out in Haughton v. Smith that it is not the actus which is reus but the man and his mind respectively.
ANALYSIS OF GENOCIDE AND INSURGENCY IN NORTHERN NIGERIA