Is corroboration required for a grand jury indictment?

Petitioner next points out that in the instant case, the prosecutor informed the grand jury that corroboration was required, and he complains that by changing its legal position, the prosecution is trifling with the courts and the parties. The theory of trial doctrine is a well-established rule of appellate practice. [Citation.] The application of this doctrine is discretionary, however, and several exceptions have developed. One of the recognized exceptions is that a party may elect to change his [or her] theory if the issue only involves a question of law. [Citation.] (Fenton v. Board of Directors (1984) 156 Cal.App.3d 1107, 1113, 203 Cal.Rptr. 388.) Here, the issue before us--whether uncorroborated accomplice testimony can support a grand jury indictment--

[182 Cal.Rptr.3d 927]