The Assistant Attorney General in charge of the Antitrust Division of the Department of Justice shall designate an antitrust investigator to serve as custodian of documentary material, answers to interrogatories, and transcripts of oral testimony received under this chapter, and such additional antitrust investigators as he shall determine from time to time to be necessary to serve as deputies to such officer.

Any person, upon whom any demand under section 1312 of this title for the production of documentary material has been duly served, shall make such material available for inspection and copying or reproduction to the custodian designated therein at the principal place of business of such person (or at such other place as such custodian and such person thereafter may agree and prescribe in writing or as the court may direct, pursuant to section 1314(d) ^[1] of this title) on the return date specified in such demand (or on such later date as such custodian may prescribe in writing). Such person may upon written agreement between such person and the custodian substitute copies for originals of all or any part of such material.