The Deputy Senate President, Ike Ekweremadu, is in the custody of the Economic and Financial Crimes Commission (EFCC).
Ekwewreamdu is said to be undergoing interrogation by the office of the agency.
Ekweremadu arrived at the office of the EFCC early yesterday on the invitation of the anti-graft body, and has not been released.
The EFCC had earlier sent an invitation to the deputy speaker for questioning over an alleged case of conspiracy, abuse of office and money laundering.
The invitation letter dated July 24, 2018, requested that the Ekweremadu should appear at the EFCC office by 10:00 am on the same date.
The commission, in the letter, said Ekeweremadu is being invited because his name featured prominently in the case which they are currently investigating, hence the invitation to obtain certain clarifications from him.
This was after security operatives stormed his home at the Apo legislative quarters in Abuja.
The deputy Senate President has come under the scrutiny of the EFCC following allegations of a corruption including owning of several buildings outside Nigeria and alleged forgery of Senate standing rules which led to the controversial election of principal officers of the Senate in June 2015.