Turnah served as special adviser to Dan Abia, ex-managing director of the Niger Delta Development Commission (NDDC).
He was arrested in Port Harcourt, Rivers state capital, in connection with alleged possession of funds running into N2 billion.
The money, according to the EFCC, was suspected to have been stolen from the NDDC.
The EFCC said preliminary investigations showed that he made deposits in his personal and company bank accounts in excess of N2billion.
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It said a search conducted in his houses in Port Harcourt and Yenogoa, Bayelsa state capital, yielded useful documents.
The commission said Turnah had made useful statements, and will soon be arraigned.
The suspect runs George Turnah Foundation, which was established in 2011. The non-profit organisation is into philanthropy.
He holds the national honour of Member Order of the Niger (MON)