N.Y.C. Admin. Code § 8-403: § 8-403 Investigation.

The corporation counsel may initiate any investigation to ascertain such facts as may be necessary for the commencement of a civil action pursuant to section 8-402, and in connection therewith shall have the power to issue subpoenas to compel the attendance of witnesses and the production of documents, to administer oaths and to examine such persons as are deemed necessary.