An authoritative source in the EFCC disclosed this to newsmen on Saturday in Abuja.
The source said the former governor was being interrogated over the alleged misapplication of N5 billion Sure-P and N37 billion security vote, withdrawn in cash.
According to the source, part of the funds was also allegedly diverted to finance political activities in the state.
The Commission on Friday told newsmen that the former governor was in its custody undergoing interrogation after his arrest on March 17.
Obiano was arrested on Thursday at Murtala Mohammed International Airport, Lagos and brought to Abuja on Friday morning.
The Commission said the former governor had not been released.
Obiano was arrested by EFCC on Thursday night, hours after handing over to the new Anambra Governor, Prof. Chukwuma Soludo.
