The evidence warranted a conclusion that the defendant was guilty either as a principal or a joint venturer, and such a determination is proper. See Commonwealth v. Podlaski, 377 Mass. 339, 345 (1979); Commonwealth v. Britt, 358 Mass. 767, 769-770 (1971). In these circumstances, the absence of direct proof by way of an eyewitness who saw the defendant shoot the victims is not damaging to the Commonwealth's case so long as there is competent circumstantial evidence that establishes the defendant's guilt, either directly or as a joint venturer, beyond a reasonable doubt.
The jury were not bound to believe that Corbett was a mere chauffeur. See Commonwealth v. Britt, 358 Mass. 767, 770 (1971) (jury not bound to believe defendant was a mere bystander). There was no error in the denial of Corbett's motion.
Furthermore, the Commonwealth need not have established which one of the group fired the shots. See Commonwealth v. Britt, 358 Mass. 767, 769 (1971). We consider the essence of the factual pattern at issue to be distinguishable from that of such cases as Commonwealth v. Clark, 363 Mass. 467 (1973), upon which the defendants rely.
The evidence warranted the conclusion that the defendant was not merely an innocent bystander, but was guilty either as a joint venturer or as a principal. See Commonwealth v. Scanlon, 373 Mass. 11, 17-19 (1977); Commonwealth v. Britt, 358 Mass. 767, 769-770 (1971). Moreover, the evidence warranted such a finding on either of two theories of murder in the first degree.
See Commonwealth v. Fiore, 364 Mass. 819, 824 (1974); Dirring v. United States, 328 F.2d 512, 514 (1st Cir. 1964); Zimberg v. United States, 142 F.2d 132, 136-137 (1st Cir.), cert. denied, 323 U.S. 712 (1944). See also Commonwealth v. Britt, 358 Mass. 767, 770 (1971). Credibility is a question for the jury to decide; they may accept or reject, in whole or in part, the testimony presented to them.
See Commonwealth v. Gricus, 317 Mass. 403, 407 (1944). See also Commonwealth v. Britt, 358 Mass. 767, 770 (1971); Commonwealth v. French, 357 Mass. 356, 397-398 (1970), judgments vacated as to the death penalty sub nom. Limone v. Massachusetts, 408 U.S. 936 (1972). 2.
We summarily reject the defendant's argument and conclude that the evidence was sufficient to warrant a jury in finding that, at the very least, the defendant had participated in a plan to beat the victim with her fists. See Commonwealth v. Britt, 358 Mass. 767, 769 (1971). Whether the defendant could be found guilty of an armed assault with intent to murder and assault and battery by means of a dangerous weapon turns on the sufficiency of the Commonwealth's proof of a joint enterprise. "The theory underlying joint enterprise is that one who aids, commands, counsels, or encourages commission of a crime while sharing with the principal the mental state required for the crime is guilty as a principal. . . . The jury may infer the requisite mental state from the defendant's knowledge of the circumstances and subsequent participation in the offense.