The director may order testimony to be taken by deposition in any proceeding or investigation pending under this chapter at any stage of such proceeding or investigation. Such depositions may be taken before any person designated by the director and having power to administer oaths. Such testimony shall be reduced to writing by the person taking the deposition, or under his direction and shall then be subscribed by the deponent. Any person may be compelled to appear and depose, and to produce documentary evidence in the same manner as witnesses may be compelled to appear and testify and produce documentary evidence before the director as previously provided.