Iowa Constitution Art. I, § 11. When indictment necessary--grand jury

All offenses less than felony and in which the maximum permissible imprisonment does not exceed thirty days shall be tried summarily before an officer authorized by law, on information under oath, without indictment, or the intervention of a grand jury, saving to the defendant the right of appeal; and no person shall be held to answer for any higher criminal offense, unless on presentment or indictment by a grand jury, except in cases arising in the army, or navy, or in the militia, when in actual service, in time of war or public danger.

The grand jury may consist of any number of members not less than five, nor more than fifteen, as the general assembly may by law provide, or the general assembly may provide for holding persons to answer for any criminal offense without the intervention of a grand jury.