Commonwealth v. Rivera

At trial on a charge of assault and battery by means of a dangerous weapon, the defense attempted to establish that the defendant acted in self-defense to repel an attack by the much larger, albeit unarmed, complainant. A District Court jury of six heard conflicting accounts of the episode from prosecu*860tian and defense witnesses. On appeal, the defendant claims that errors of three types impermissibly bolstered the credibility of the prosecution’s witnesses and tarnished the credibility of the defense. We conclude that the cumulative effect of the errors requires reversal of the judgment of…