To prevail on a post-trial claim that a grand jury indictment was wrongly procured through perjury, a defendant must show prejudice at trial. At a grand jury hearing, a gang associate of appellant testified that while at a party, he heard appellant confess to the killings. The associate lied and claimed that he was not present at the killings. However, at the subsequent trial, he admitted that he had lied to the grand jury when he falsely testified that he had not been present. Because the lie was revealed and clarified at trial, appellant suffered no prejudice from the perjured testimony at the grand jury hearing, so as to render any error in the grand jury proceeding harmless.