In Twiggs v. Superior Court (1983) 34 Cal.3d 360, the defendant's first trial resulted in a hung jury. Before the retrial, the prosecutor added five prior felony conviction allegations which had not been alleged in the first trial. The existence of the prior convictions was known at the time of the first trial. The amendment of the information to add the prior conviction allegations was presumptively vindictive. The California Supreme Court remanded for a hearing to determine whether the filing of the allegations was in fact retaliatory. (Id. at p. 375.)