The district court’s conditional grant of Alcala’s habeas petitioned was affirmed where there were multiple constitutional errors in a capital case which had a substantial and injurious effect on the jury’s determination of guilt. First, Alcala’s counsel provided ineffective assistance of counsel when he failed to adequately present his alibi defense by failing to put forth evidence which was available. Counsel’s inability to recollect why he did not present the evidence did not compel a conclusion that his actions were reasonable tactical decisions. The error was prejudicial because the prosecution’s case was far from compelling, and the absence of the alibi evidence prejudiced his case. Second, the exclusion of defense expert testimony that a key prosecution witness’s testimony had been hypnotically induced by police investigators violated Alcala’s due process right to a fundamentally fair trial and to present crucial witnesses in his defense. Further, the combined prejudice of the multiple errors committed provided a separate and independent basis for granting the petition. These included the exclusion of certain defense witnesses, admission of unused kitchen knives from Alcala’s home, and additional failures by defense counsel to investigate the evidence.