Power to conduct investigations (National Assembly)
Section 88(1) · 1999 Constitution (2004 edition)
What Constitution says
(1) Subject to the provisions of this Constitution, each House of the National Assembly shall have power by resolution published in its journal or in the Official Gazette of the Government of the Federation to direct or cause to be directed investigation into - (a) any matter or thing with respect to which it has power to make laws, and (b) the conduct of affairs of any person, authority, ministry or government department charged, or intended to be charged, with the duty of or responsibility for - (i) executing or administering laws enacted by National Assembly, and (ii) disbursing or administering moneys appropriated or to be appropriated by the National Assembly.
This is the 1999 Constitution as published in 2004. Later amendments aren't included yet, so a section may have changed since.
Original source
Official Gazette · CFRN 1999 official PDF · printed page 55. Original document
Release: draft-c8d50d87fae9. Source scope, review and corrections