Idaho R. Crim. P. 6.6
A motion to dismiss the indictment may be granted by the district court on any of the following grounds:
. a valid challenge to the array of grand jurors;
. a valid challenge to an individual juror who served on the grand jury that found the indictment, except that finding of the valid challenge to one or more members of the grand jury is not grounds for dismissal of the indictment if there were 12 or more qualified jurors concurring in the finding of the indictment;
. that the charge in the indictment was previously submitted to a magistrate at preliminary hearing and dismissed for lack of probable cause; or
. that the indictment was not properly found, endorsed and presented as required by these rules or by the statutes of the state of Idaho.
Id. Crim. R. 6.6