Iowa Code § 626.49: Where secured party garnished.

If the secured party, before the levy of a writ of attachment or execution, has been garnished at the suit of a creditor of a debtor, a creditor desiring to seize the collateral under a writ of attachment or execution shall pay to the secured party, or deposit with the clerk, in addition to the secured debt, the sum claimed under the garnishment, and the provisions of this chapter, so far as applicable, in all respects shall govern proceedings relating thereto.