The Economic and Financial Crimes Commission, EFCC, few days ago arrested the former Secretary to Government of the Federation, Babachir Lawal.
Mr. Lawal was arrested Wednesday, Channels Television reported.
Mr. Lawal was recently sacked after he was indicted by a presidential panel that investigated misuse of funds meant for people displaced by Boko Haram.
He had earlier been indicted by the Senate.
His arrest is coming a day after former President Olusegun Obasanjo accused Mr. Buhari of condoning corruption where persons close to him are involved.
Mr. Obasanjo said in a statement that the president had failed woefully, and urged him not to seek re-election.
He released on bail two days later.
EFCC sources confirmed that he has been allowed to go home on administrative bail.
He was invited for interrogation on Wednesday by the EFCC, over alleged N223million contract scams awarded at some IDP camps in Yobe State.
Mr Samin Amaddin, Acting Head of Media and Publicity of EFCC, said the former SGF was cooperating with investigators and had made useful statements.
The former SGF was accused of using his company Rholavision Engineering Ltd to corner a N230 million contract for the clearing of “evasive plant species’’ in Yobe.
The contracts were awarded through the Presidential Initiative on Northeast (PINE).
In total, Lawal’s crime, according to the ad-hoc committee, was that he spent N570 million to cut grass, part of which he awarded to himself.