Harland W. French appeals from an order of the District Court requiring him to comply with an Internal Revenue summons for the production of documents relating to his 1974 return. French challenged the summons on the grounds that it violated his Fourth and Fifth Amendment rights. A hearing was held before a magistrate, who recommended an order directing compliance with the summons. After a de novo review in which the District Court examined the relevant documents in camera, it sustained the magistrate’s findings and ordered compliance with the summons.

The District Court held that French failed to show potential incrimination or that the government was preparing a criminal case against him. It also found that the Internal Revenue Service carried its burden for enforcement of the summons and that the information sought was relevant and reasonable for the investigative purpose.

We have carefully reviewed the record and briefs and we affirm on the basis of the District Court’s opinion. United States v. French, 442 F.Supp. 166 (N.D.Iowa 1977).