Rochas Okorocha, former Imo State Governor, was arrested on Tuesday in Abuja.
Economic and Financial Crimes Commission (EFCC) operatives picked him at his private office.
EFCC Head of Media, Wilson Uwujaren, confirmed the development.
The reason is not known yet, but the Senator reportedly failed to honour invitations by the agency.
Governor Hope Uzodinma had accused Okorocha of misappropriating state funds.
In February, the lawmaker accused Uzodinma of unleashing the EFCC and the Independent Corrupt Practices Commission (ICPC) against him.
Okorocha said the state government had not been able to prove corruption allegations against him and family in court.
“I was never a poor man before I became governor of Imo state. I came here, brought my children to invest, brought everybody to invest”, he had said.