In People v. Green (1980) 27 Cal.3d 1, the defendant was convicted of murdering his wife, who died from a shotgun wound to the head. Don Sheehan, a prosecution witness, testified that he provided a shotgun to defendant the day of the murder. He testified that he had told arresting officers he was afraid to go to prison on a pending parole violation charge because defendant "'had a lot of friends there.'" (Green, supra, at p. 19.) The Supreme Court held that the testimony was admissible as relevant to Sheehan's credibility. Sheehan had testified that authorities promised him he would not be sent to prison on his parole violation. The prosecutor correctly anticipated that the defense would attack Sheehan's credibility by suggesting that this promise was a motive to give testimony favorable to the prosecution. To bolster Sheehan's credibility the prosecutor sought to show that the promise to Sheehan was solely to allay his fear of retaliation in prison. (Id. at p. 20.) The court also noted that all the principal prosecution witnesses were ex-felons who faced ostracism "or worse" if they gave information to the police. (Ibid.) The Green court held: "In the circumstances, the fact that Sheehan was willing to testify against a former member of the group despite his fear of retaliation was supportive of the credibility of his testimony." (People v. Green, supra, 27 Cal.3d at p. 20.) The court concluded the trial court did not abuse its discretion in admitting Sheehan's testimony about fear of retaliation. In addition, there were several other instances in Green in which prosecution witnesses spoke of concern for their personal safety and about protective measures taken by authorities. The defendant contended that these threats were not admissible unless linked to him. (People v. Green, supra, 27 Cal.3d at p. 20.) The Supreme Court rejected this argument, characterizing it as "misdirected" because the prosecution never claimed that the witnesses' fear was the result of any effort on the defendant's part to procure false testimony. (Ibid.) The Supreme Court set aside the jury's robbery special circumstance finding. Although the trial court had properly instructed the jury that to find the robbery special allegation true, it must first find defendant guilty of the underlying robbery, it did not instruct the jury that the murder must have been committed "'during the commission'" of the robbery. (Id. at p. 60.) The Green court held that failure to so instruct was reversible error. It reasoned that such instruction "ignored key language of the statute: it was not enough for the jury to find the defendant guilty of a murder and one of the listed crimes; the statute also required that the jury find the defendant committed the murder 'during the commission or attempted commission of' that crime. (Former 190.2, subd. (c)(3).) In other words, a valid conviction of a listed crime was a necessary condition to finding a corresponding special circumstance, but it was not a sufficient condition: the murder must also have been committed 'during the commission' of the underlying crime." (Green, supra, at p. 59.) As the court explained, "The Legislature must have intended that each special circumstance provide a rational basis for distinguishing between those murderers who deserve to be considered for the death penalty and those who do not. The Legislature declared that such a distinction could be drawn, inter alia, when the defendant committed a 'willful, deliberate and premeditated' murder 'during the commission' of a robbery or other listed felony. (Former 190.2, subd. (c)(3).) The provision thus expressed a legislative belief that it was not unconstitutionally arbitrary to expose to the death penalty those defendants who killed in cold blood in order to advance an independent felonious purpose, e.g., who carried out an execution-style slaying of the victim of or witness to a holdup, a kidnaping, or a rape." (Green, supra, at p. 61.)