Indiana Code Title 10. Public Safety § 10-16-7-10

Sec. 10. An officer whose command is called out under section 9 of this chapter and who is reporting to any civil officer may require the civil officer to make the order in writing and prescribe the outline of the duties required of the officer and the officer's command.  The officer may decline to obey the orders until the orders are put in writing.  Although the commanding officer must obey all lawful written orders of the civil officer, the military officer may use the officer's discretion as to the manner of carrying out the orders if the officer complies with their spirit.