Tare Akono, state NUJ chairman, said by telephone that he had handed the man over to the police for further questioning. Police spokesman Alex Akhigbe confirmed this, but said the case was still being investigated.
"Attempts by the fake journalist to affirm his genuineness led to the discovery of a fake CNN identification card in his bag," Akono said, adding that he actually worked for a local station called Radio Rivers.
A CNN correspondent covering Nigeria confirmed the man was not working for the cable network. Akono said he was suspected of using the ID to persuade officials to give him money in exchange for positive documentaries about their work.
Although very free by the standards of the region, Nigeria's press is often corrupt, with journalists and editors both taking backhanders to write favourable stories about their sponsors -or poisonous ones about their sponsors' enemies. Many journalists are paid little, late or not at all and so rely on cash from the subjects of their reporting just to make ends meet.