Misconduct by the prosecution can so infect the trial with unfairness that the conviction will result in a denial of due process. Here, the prosecutor told the jury in closing argument, in addition to less egregious acts of misconduct [i.e., vouching for witnesses, arguing matters outside the evidence, and denigrating defense counsel], that the defense was required to produce evidence regarding the police officer’s credibility, such that the burden of proof was impermissibly shifted to the defense. The effect of the prosecution’s misconduct was further enhanced by the court’s overruling of the defense objections and could not be dissipated by an instruction that statements to the jury are not evidence. Because the prosecutor’s arguments were of federal constitutional magnitude, the cumulative effect of the misconduct was assessed under Chapman v. California (1967) 386 U.S. 18, 24– respondent being required to prove beyond a reasonable doubt that the error did not contribute to the verdict, which he was not able to do. Accordingly, the judgment was reversed. The court also addressed the prosecution’s intimidation of a defense witness by entering into a plea bargain with the witness that was conditioned on a promise by witness not to testify in appellant’s case and then threatening to attempt to undo the bargain when the witness was subpoenaed to testify. Although appellant could not establish the requisite prejudice, i.e., that there was a reasonable probability that if the witness had testified, the testimony would have been material and favorable, the court counseled the lower court to do its utmost to eliminate the “sinister effect” of the intimidation if appellant was retried.