"It is necessary to distinguish, not only between questions of guilt and questions of degree of culpability, but also between issues, facts relevant to issues, and evidence. The jury's verdict decided the issues joined by the plea to the indictment. It did not decide, either expressly or by implication, all facts of possible relevance to sentencing. And although it is possible to infer that, at the least, certain parts of the evidence must have been accepted by the jury, it is impossible to know whether some or all of the jurors accepted all of the evidence relied upon by the prosecution. Jurors are normally instructed that they are entitled to choose between parts of the evidence. In order to convict they must find, beyond reasonable doubt, the constituent elements of the offence charged, but provided they reason to such a conclusion in a manner consistent with properly framed judicial directions, their process of reasoning does not necessarily have to be unanimous. Unless a particular piece of evidence is logically crucial to the prosecution case they do not have to accept, beyond reasonable doubt, any particular witness, or any particular evidence. These are familiar aspects of what is sometimes described as the inscrutability of a jury verdict." (Emphases added).