In an amended 39 counts charge, they were accused by EFCC of conspiring and diverting over N7 billion from the coffers of the state.
Mr Maigandi said the incident occurred when the canoe capsized while ferrying the victims across Tindifai River on Monday.
Two policemen were also killed during the incident.
An electric power accident has been reported at the Ikoyi Prison, a major correctional facility in Lagos.
Two village heads, the chairman of a vigilante group and two other persons were killed
Mr Onyema was indicted by a federal grand jury in the United States on November 19.
His kidnap has sparked tension in the Nsukka suburb of Enugu.