Nigeria has arrested the co-chairman of local oil firm Atlantic Energy to question him over corruption and money laundering charges, an official at the Economic and Financial Crimes Commission said Oct. 6.

The official, who asked not to be named, said prominent businessman Jide Omokore was being investigated in connection with a crackdown on corruption in the oil sector that has swept up former oil minister Diezani Alison-Madueke, who was arrested last week in London.

Alison-Madueke was minister from 2010 until May 2015 under former president Goodluck Jonathan, who was defeated by Muhammadu Buhari at the polls in March.

Buhari took office in May promising to root out corruption in Africa's most populous country, where few benefit from the OPEC member's enormous energy resources.

Former central bank governor Lamido Sanusi was removed during Alison-Madueke's tenure after he raised concerns that tens of billions of dollars in oil revenues had not been remitted to state coffers by the government-run oil company NNPC between January 2012 and July 2013.

She has denied any wrongdoing but was criticized by Sanusi for handing out contracts to Atlantic, a new company, shortly after becoming oil minister.

The financial crimes unit has sealed one of her houses in Abuja as part of the probe, security sources have told Reuters.