A former vice president of Citigroup has pleaded not guilty to charges that he embezzled more than $19 million in a case that prosecutors are calling the “ultimate inside job.”

Federal prosecutors say Gary Foster funneled money from various Citigroup bank accounts to his personal account in eight separate wire transfers between July and December of last year.

Prosecutors allege that Foster used his insider knowledge of bank operations to make the wire transfers appear legitimate. Foster worked in the company's treasury finance department.

Foster was set free on $800,000 bail after appearing in a federal court Monday. He was arrested Sunday morning at John F. Kennedy Airport in New York after returning from a trip to Thailand. Authorities say Foster could spend up to 30 years in prison if convicted of the charges.

Prosecutors say Citigroup informed the Federal Bureau of Investigation about Foster's alleged fraud after a recent internal audit of the company's treasury department. Citigroup says it is cooperating with federal authorities and hopes to see Foster “prosecuted to the full extent of the law.”