SDCL § 21-18-42: Defense of garnishment proceedings by principal defendant--Grounds.

The principal defendant may in all cases by answer duly verified, to be served within thirty days from the service of the garnishee summons on him, defend the proceeding against any garnishee upon the ground that the indebtedness of the garnishee, or any property held by him, is exempt from execution against such defendant or for any other reason is not liable to garnishment; or upon any ground upon which a garnishee might defend the same; and may participate in the trial of any issue between the plaintiff and garnishee for the protection of his interests.