Mamman Nasir Ali is the son of former Chairman of Peoples Democratic Party (PDP), Ahmadu Ali.

Justice Mojisola Dada of the Special Offences Court in Ikeja, Lagos, on Tuesday, May 27, 2025, convicted and sentenced oil marketers Mamman Nasir Ali and Christian Taylor to 14 years in prison each for their involvement in a ₦2.2 billion oil subsidy fraud.

Mamman Nasir Ali is the son of former Chairman of Peoples Democratic Party (PDP), Ahmadu Ali.

The two were re-arraigned along with their company, Nasaman Oil Services Limited, on an amended 57-count charge following new revelations in the case.

They were originally arraigned on a 49-count charge involving conspiracy to obtain money by false pretence, forgery, and the use of false documents.

One of the counts reads: "Nasaman Oil Services Ltd, Mamman Nasir Ali, Christian Taylor, Oluwaseun Ogunbambo (now at large) and Olabisi Abdul-Afeez (still at large), on or about the 9th day of November 2011 at Lagos, within the Ikeja Judicial Division, with intent to defraud, conspired to obtain the sum of N749,991,273.36 (Seven Hundred and Forty-Nine Million, Nine Hundred and Ninety-One Thousand, Two Hundred and Seventy-Three Naira Thirty-six Kobo) from the Federal Government of Nigeria by falsely claiming that the sum of N749,991,273.36 represented subsidy accruing to Nasaman Oil Services Ltd under the Petroleum Support Fund for the importation of 10,031,986 litres of Premium Motor Spirit (PMS), which Nasaman Oil Services Ltd purported to have purchased from SEATAC Petroleum Ltd of British Virgin Islands and imported into Nigeria through MT Liquid Fortune Ltd of British Virgin Islands and imported into Nigeria through MT Liquid Fortune Ltd Ex MT Overseas Lima, which representation you knew to be false."

Another count reads: "Nasaman Oil Services Ltd, Mamman Nasir Ali, Christian Taylor, Oluwaseun Ogunbambo (now at large) and Olabisi Abdul-Afeez (still at large),on or about the 11th day of April 2011 at Lagos, within the Ikeja Judicial Division, with intent to defraud,  obtained the sum of N1,480,074,125.61 (One Billion Four Hundred and Eighty Million, Seventy-Four Thousand, One Hundred and Twenty-Five Naira Sixty-One Kobo) from the Federal Government of Nigeria by claiming that the sum represented subsidy accruing to Nasaman Oil Services Ltd under the Petroleum Support Fund for the importation of 20,492,982.50 litres of Premium Motor Spirit (PMS),which Nasaman Oil Services Ltd purported to have purchased from SEATAC Petroleum Ltd of British Virgin Islands and imported into Nigeria through MT Liquid Fortune Ex Mt. Hellenic Blue and Ex MT. Milleura, which representation you knew to be false."

They pleaded not guilty to all the charges preferred against them.

They were initially standing trial before Justice Adeniyi Onigbanjo of the Lagos State High Court sitting in Ikeja, Lagos.

However, Justice Onigbanjo withdrew from the case, thereby prompting the re-assignment of the case to Justice Dada.

During the trial, the prosecution, led by Seiduh Atteh, presented witnesses and tendered documents, which were admitted by the court, to prove its case against the defendants.

Delivering judgment on Tuesday, Justice Dada found the evidence presented by the prosecution compelling and held that the actions of the defendants not only defrauded the government but also undermined the integrity of Nigeria’s oil subsidy programme.