How have the courts dealt with impermissible police conduct in the context of sexual assault cases?

84. It is not fruitful, in my view, to deal with impermissible police conduct through the vehicle of substantive criminal law doctrine. There are three problems with the appellant's proposition. Firstly, the conduct of the police or their agents in most cases will not have the effect of negating mens rea or, for that matter, actus reus. (There may be exceptional cases, however; see, for example, the decision of this Court in Lemieux v. The Queen, 1967 CanLII 9 (SCC), [1967] S.C.R. 492.) The physical act of the accused is a voluntary one and the accused will have an aware state of mind. The prohibited act will have been committed intentionally and with knowledge of the facts which constitute the offence and the consequences which flow from them.