actus reus means the guilty act and is one element the prosecution must prove in a criminal case
All crimes require actus reus. That is, a criminal act or an unlawful omission of an act, must have occurred. A person cannot be punished for thinking criminal thoughts. This element is based on the problem of standards of proof. How can another person's thoughts be determined and how can criminal thoughts be differentiated from idle thoughts? Further, the law's purview is not to punish criminal ideas but to punish those who act upon those ideas voluntarily.
Element (criminal law)