In People v. Laney (1981) 115 Cal.App.3d 508, the court "concluded and held that the rule announced in People v. Pompa-Ortiz (1980) 27 Cal.3d 519. . . applies also to grand jury proceedings." (Laney, supra, 115 Cal.App.3d at p. 513.) The prosecution had arguably violated its duty to disclose exculpatory evidence to the grand jury by withholding statements that impeached a witness's credibility. (Id. at p. 512.) The court held "the irregularities, if any there be, require reversal only if an accused can show he was deprived of a fair trial or otherwise suffered prejudice." (Id. at p. 513.) In determining whether the defendant had a fair trial, the court noted "the allegedly exculpatory evidence set out above was not pursued or brought out at trial." Thus, because "the trial was fair," the prosecution's failure to disclose the impeaching statements to the grand jury was harmless. (Ibid.) Laney is directly on point. Defendant must show prejudice at trial to prevail on a post-trial claim that the indictment was wrongly procured through perjury. (Laney, supra, 115 Cal.App.3d at p. 513.)