concurring and dissenting:
The appellant was convicted of indecent exposure and corrupting the morals of a minor. I concur with the majority that the Commonwealth did not prove the charge of corrupting the morals of a minor. I would, however, affirm the conviction of the appellant upon the charge of indecent exposure and, therefore, dissent from that portion of the majority opinion.
A person may be convicted of indecent exposure “if, for the purpose of arousing or gratifying sexual desire of himself or any other person other than his spouse, he exposes his genitals under circumstances in which he knows his conduct is likely to cause affront or alarm.” 18 Pa.C.S.A. § 3127.
The majority concludes that the Commonwealth’s evidence was insufficient to prove that he acted for the purpose of arousing or gratifying sexual desire because there was no evidence that appellant was masturbating or had an erection and because all we know is that appellant faced a wall, extracted his penis and shook it which is as consistent with urination as it is with a sexual act. I respectfully disagree.
*355It must be remembered that in testing the legal sufficiency of the evidence to support the verdict, the reviewing court is not permitted to substantiate [sic] its judgment for that of the factfinder. The reviewing court is restricted to assessing the evidence in the light most favorable to the verdict winner, here the Commonwealth, and drawing all proper inference that the evidence suggests in that party’s favor.
Commonwealth v. Smith, 490 Pa. 374, 378, 416 A.2d 517, 519 (1980). Moreover, “[p]roof of a defendant’s state of mind ‘may be found in the defendant’s words or conduct or from the attendant circumstances together with all reasonable inferences therefrom.’ ” Commonwealth v. Stoffan, 228 Pa. Super.Ct. 127, 149, 323 A.2d 318, 328 (1974) (quoting Commonwealth v. Freeman, 225 Pa.Super.Ct. 396, 399, 313 A.2d 770, 772 (1973) (citations omitted). Additionally, the finder of fact may find that the actor intended the natural and probable consequences of his actions. Commonwealth v. Thomas, 465 Pa. 442, 350 A.2d 847 (1976); Commonwealth v. Back, 255 Pa.Super.Ct. 603, 389 A.2d 141 (1978). In view of the above tests, we believe that the Commonwealth’s evidence in the instant case was clearly sufficient to enable the trier of the fact to convict appellant of indecent exposure.
The testimony quoted in the majority opinion reveals we know much more than the fact that appellant faced a wall, extracted his penis and shook it. In determining the sufficiency of the evidence, we must consider all of the evidence and all of the reasonable inferences in the light most favorable to the Commonwealth. Commonwealth v. Martin, 481 Pa. 515, 393 A.2d 23 (1978) (emphasis added). Significantly, the evidence also indicates that appellant was aware that a young girl was present in the alley only several feet from him and that he chose to expose his genitals in a manner that permitted her to view them.
I differ with the conclusion of the majority that there was insufficient evidence because the appellant’s conduct was as consistent with urination as it was with a sexual act. The trial judge, who was the trier of the facts, concluded there *356was sufficient evidence of the sexual nature of the pertinent behavior. It is not the function of an appellate court, in an appeal alleging insufficiency of evidence, to weigh the evidence and substitute its judgment. Commonwealth v. Zimmerman, 264 Pa.Super.Ct. 307, 399 A.2d 1064 (1979). Moreover, circumstantial evidence may be sufficient if the circumstances are consistent with criminal activity even though they might also be consistent with innocent behavior. Commonwealth v. Adams, 273 Pa.Super.Ct. 484, 417 A.2d 751 (1979).