The Economic and Financial Crimes Commission (EFCC) has asked the ex-First Lady to come before a court by entering into a plea bargain in line with the laws of the land.
The agency said it would only accept a plea bargain in which the court is carried along.
Also, EFCC detectives have not been able to trace about 29 of the 31 individuals and companies which made the controversial deposits.
The development has fuelled speculations that some of the depositors are “fictitious”.
Some of the shops where the ex-First Lady visited are said to have offered to give details of how much was spent and the items bought.
The EFCC believes that an out-of-court settlement suggests that there is a dispute between two parties.
A source, who spoke in confidence, said: “We have considered the January 30, 2018 letter by Dame (Mrs.) Ibifaka Patience Jonathan; we are of the opinion that her offer of out-of-court settlement is strange and confounding as if there is a dispute between her and the EFCC.
“We are certainly rejecting the offer from the ex-First Lady because the EFCC does not engage in such a deal.
“But we prefer the ex-First Lady approaching a court for plea bargain in line with the relevant laws if she is ready to settle all issues. The terms of the plea bargain will be open to all parties before the court.
“I think she should emulate other high profile suspects who went to the court for plea bargain. We are ready to apply the laws in the interest of justice for all. We won’t oppose plea bargain.”
The source said the EFCC would soon make its position known to Mrs Jonathan counsel. “As an officer in the Temple of Justice, we know that the respected Senior Advocate of Nigeria(SAN) will guide the ex-First Lady accordingly,” he said.