"Every man is presumed to be sane and to possess a sufficient degree of reason to be responsible for his crimes until the contrary is proved to the satisfaction of the trier of fact." Jones v. Commonwealth, 202 Va. 236, 239-40, 117 S.E.2d 67, 70 (1960). The burden of proving insanity rests on the individual asserting it as a defense. See Fines v. Kendrick, 219 Va. 1084, 254 S.E.2d 108 (1979). "When the corpus delicti has been established and proof adduced that the accused committed the act, it is not sufficient for the accused to raise a reasonable doubt as to his sanity; he must go one step further and prove to the satisfaction of the trier of fact that he was insane at the time of the commission of the act." Taylor v. Commonwealth, 208 Va. 316, 322, 157 S.E.2d 185, 190 (1967). In Wessells v. Commonwealth, 164 Va. 664, 180 S.E. 419 (1935), the Supreme Court of Virginia elaborated on this standard stating: The Commonwealth, having established the corpus delicti, and that the act was done by the accused, has made out her case. If the accused relies on the defense of insanity, he must prove it to the satisfaction of the jury. If, upon the whole evidence, they believe he was insane when he committed the act, they will acquit him on that ground; but not upon any fanciful idea that they believe he was then sane, yet, as there may be a rational doubt of such sanity, he is therefore entitled to an acquittal. Insanity is easily feigned and hard to be disproved, and public safety requires that it should not be established by less than satisfactory evidence. Wessels, 164 Va. at 674, 180 S.E. at 423.