The sources told newsmen that Mr. Abati told interrogators that he had no immediate means of sourcing the amount for which he is being detained.
The EFCC accuses Mr. Abati of receiving N50 million from the former National Security Adviser, Sambo Dasuki.
The money was part of $2.1 billion allocated for purchase of arms for the fight against Boko Haram, the EFCC says.
Mr. Dasuki is currently standing trial for allegedly misusing the money.
The latest development came days after Mr. Abati reportedly promised to refund N5 million.
The former presidential spokesperson has been in EFCC detention since turning himself in last week Monday.
Apart from being unable to refund the money, Mr. Abati also allegedly told investigators that he could not provide documentary evidence showing how he spent the N50 million.
Mr. Abati reportedly said he disbursed the money as cash and material gifts to journalists during the 2015 campaign.
Asked to name names of media practitioners who benefited from the largess, Mr. Abati said he did not keep such records.
“We thought he would be able to pay N5 million yesterday, but it turned out that he doesn’t have any money,” a source told PREMIUM TIMES Monday.
Our source also clarified that Mr. Abati had met his bail conditions since Friday, but the EFCC had refused to release him.
The EFCC had on October 26 granted Mr. Abati an administrative bail, and required as one of the conditions for his release, a surety of the level of director in the federal civil service.
Those conditions were met on Friday, our source said, but the EFCC failed to release him because of the stalemate over the N50 million.
The EFCC spokesman, Wilson Uwujaren, did not respond to requests for comment.