<P> In general, men's rea and actus reus must occur at the same time--that is, the criminal intent must precede or coexist with the criminal act, or in some way activate the act . The necessary mens rea may not continually be present until the forbidden act is committed, as long as it activated the conduct that produced the criminal act . However, for criminal liability to occur, there must be either overt and voluntary action </P> <P> Many crimes include an element that actual harm must occur--in other words, causation must be proved . For example, homicide requires a killing, aggravated battery requires serious bodily injury and without those respective outcomes, those respective crimes would not be committed . A causal relationship between conduct and result is demonstrated if the act would not have happened without direct participation of the offender . </P> <P> Causation is complex to prove . The act may be a "necessary but not sufficient" cause of the criminal harm . Intervening events may have occurred in between the act and the result . Therefore, the cause of the act and the forbidden result must be "proximate", or near in time . </P>

Three factors necessary for the commission of a crime