Removal of President from office
Section 143(5) · 1999 Constitution (2004 edition)
What Constitution says
(5) Within seven days of the passing of a motion under the foregoing provisions, the Chief Justice of Nigeria shall at the request of the President of the Senate appoint a Panel of seven persons who in his opinion are of unquestionable integrity, not being members of any public service, legislative house or political party, to investigate the allegation as provide in this section.
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 71–72. Original document
Release: draft-c8d50d87fae9. Source scope, review and corrections