We learned on Sunday that the began questioning a former Senate President, Pius Anyim, in a case of alleged corruption and misappropriation of public funds.
Mr Anyim, who served as Senate President from 2000 to 2003, was named Secretary to the Government of the Federation by then-President Goodluck Jonathan in 2011, a position he maintained until 2015.
Mr Anyim arrived to the commission's offices in Abuja at 3 p.m. on Sunday, according to EFCC sources with firsthand knowledge of the case against him.
Mr Anyim was still being interrogated by anti-graft agents at the time of reporting this story.
Sources stated the allegations against Mr Ayim are related to a case involving the sitting Anambra North senator, Stella Oduah, however details of the exact allegations against him were unclear as of press time.
Ms. Oduah was also the Minister of Aviation under President Goodluck Jonathan from 2011 until 2014, when she was fired due to a contract scandal involving the acquisition of BMW armoured cars.
According to EFCC sources, she is being investigated for a fraud accusation involving a rehabilitation fund of N780 million that was reportedly routed to a firm owned by the former Senate President.
Wilson Uwujaren, a spokesman for the EFCC, said he had not been bribed when contacted.
Ms Oduah is currently being investigated by the EFCC, along with China Civil Engineering Construction Corporation (CCECC) Nigeria Ltd and other defendants, on separate money laundering charges totalling N5 billion.
She allegedly committed the crimes during the final months of her employment as the aviation minister and continued after she was fired.
Her riches concealed in tax havens were revealed in the recently leaked Pandora Papers.
Mr Anyim, for his part, has been identified in connection with alleged financial irregularities involving the Abuja-based Centenary City project.
The committee lead by a House member, Herman Hembe, is claimed to have filed the report indicting Mr Anyim to the House of Representatives.
Mr Anyim sued the House of Representatives in 2017 through his lawyer, Mike Ozekhome, denying any misconduct.
U. A Musale, a judge of the FCT High Court, granted an injunction preventing the House from acting on the report on May 4, 2017.
