(CNN)-- A Nigerian man who supervised more than 30 private security guards at Newark-Liberty International Airport pleaded not guilty Tuesday to identity theft of a man killed in New York two decades ago, prosecutors said.
Bimbo Olumuyiwa Oyewole, 54, is accused of using the identity of Jerry Thomas and taking up work as a security guard by way of a phony name.
"His resume indicates that he was hired in March of 1992, and we are in the process of trying to independently verify that is correct," said Port Authority spokesman Steve Coleman.
Authorities initially reported that Thomas was believed to have died before his identity was stolen. But Coleman said that new evidence suggests that he was killed afterward.
Officials say Oyewole is an illegal immigrant from Nigeria but passed numerous background checks with the New Jersey State Police and Border Protection.
An anonymous tip several weeks ago helped investigators build a case, Coleman said. Oyewole was arrested at his home in Elizabeth, New Jersey, on Monday and charged with identity theft.
Details of Thomas' death in 1992 were not clear Monday, but the New York Police Department said it had no information linking Oyewole to any investigation.
Oyewole worked at four private security companies over the past 20 years, most recently with FJC Security since 2003. He had access to various secure areas of the airport, including the runways, according to Coleman of the Port Authority.
His attorney could not be immediately reached for comment.
Oyewole is set to be formally arraigned on June 18.