N.Y.C. Charter § 455: Section 455. Cooperation of the police department.

a. It shall be the duty of the police department to provide such assistance as the board may reasonably request, to cooperate fully with investigations by the board, and to provide to the board upon request records and other materials which are necessary for the investigation of any matter within its jurisdiction pursuant to this chapter, except such records or materials that cannot be disclosed by law.

b. The police commissioner shall ensure that officers and employees of the police department appear before and respond to inquiries of the board in connection with the investigation of any matter within the board's jurisdiction pursuant to this chapter, provided that such inquiries are conducted in accordance with department procedures for interrogation of members.