The Nigeria Immigration Service has said it is investigating the alleged extortion of a United States-based Nigerian Professor, Moyo Okediji, by men of the service. Okediji had on Tuesday taken to his Facebook page to post about how he gave $40 to some immigration officers who accosted him at the Seme border and demanded to be “settled” after they conducted a search on him. Okediji, a Professor of Arts and History at the University of Texas, United States, wrote that after he was released by the men of the Immigration, whom he said “were many”, he discovered that $500 had…