Ibrahim Magu has been suspended as Acting chairman of the Economic and Financial Crimes Commission (EFCC) by President Muhammadu Buhari, the BBC reports.
Magu spent the night in a police cell at the Force Criminal Investigation Department (FCID) Headquarters in Abuja.
This followed a six-hour grilling by a presidential panel, chaired by Justice Ayo Salami, a former president of the Court of Appeal.
Buhari set up the panel to probe various allegations levelled against Magu, following a petition by the Minister of Justice and Attorney General of the Federation, Abubakar Malami, and the Department of State Service DSS