Iowa Code § 641.2: Attachment authorized.

In all actions for money due to the state, or to any agent or officer for the use of the state, it shall be lawful for an attachment to issue against the property or debts of the defendant not exempt from execution, upon the filing of an affidavit of the attorney general, that the attorney general verily believes that a specific amount therein stated is justly due, and the defendant therein has refused to pay or secure the same, and unless an attachment is issued against the property of the defendant there is danger that the amount due will be lost to the state.