Nigeria has arrested the chairman of a local oil firm, a security official said on Tuesday, as part of a widening graft investigation in Africa's biggest petroleum producer that has also netted former oil minister Diezani Alison-Madueke.
Reuters reports that days after British police detained Alison-Madueke, one of Africa's most powerful women, the official said Nigeria's Economic and Financial Crimes Commission (EFCC) had arrested Atlantic Energy chairman Olajide Omokore on corruption and money laundering charges.
The arrests, which follow pledges by President Muhammadu Buhari to "clean up" Africa's biggest economy, have sent shockwaves through Nigeria's globe-trotting corporate and political elite.
Atlantic Energy was one of two firms that signed so-called Strategic Alliance Agreements with NNPC's upstream arm, NPDC, in May 2011 to manage oil blocks sold by oil major Royal Dutch Shell.
The second deal was signed with Seven Energy through a company called Septa Energy, of which Nigerian tycoon Kolawole Aluko was co-CEO.
In response to a Reuters query, Switzerland's office of the attorney general said it had received a request from Nigeria for "mutual assistance" in connection with Mr. Aluko and energy firms linked to him.