Malami had claimed that the money was for the two Nigerian lawyers hired to complete the Abacha loot recovery but Adeosun 'suspected a foul play'.
According to The Cable, the minister also wrote a strong-worded objection letter to President Muhammadu Buhari over the payment following revelations of suspected corruption.
The Swiss government had reportedly repatriated the Abacha loot to Nigeria a few months ago following the memorandum of understanding (MoU) signed by the two countries for the judicious use of the recovery.
After the repatriation, the Attorney-General of the Federation, Abubakar Malami was said to have requested for the payment of $16.9 million (N6 billion) which he allegedly said was for the two lawyers hired to complete the legal works of the Abacha loot recovery.
The Nigerian government had since 1999 hired a Swiss lawyer, Enrico Monfrini, to facilitate the recovery of Abacha loot.
Monfrini was said to have finished the Luxembourg leg of the job since 2014 when Mohammed Bello Adoke was the attorney-general of the federation, and the Federal Government had reportedly paid Monfrini his complete fees.
The report said the recovered money was consequently domiciled with the attorney-general of Switzerland pending the signing of an MoU with Nigeria to avoid the issues of accountability around previous recoveries.
It was gathered that at this point, the services of lawyers were no longer needed as all that was left after the signing of the MoU was a government-to-government communication for the money to be repatriated to Nigeria.
Despite this, Malami was said to have curiously engaged the services of another set of lawyers in 2016 for a fee of about N6 billion.
In the MoU reached with Monfrini for the recovery, the report said it was clearly spelt out that no other lawyer would be needed for the return of the money to Nigeria.
But in Malami's defence, a recent article alleged that Monfrini was asking for an additional 20 percent to "complete the job".
The article said Malami made a counter offer of five percent which Monfrini was said to have rejected, and this reportedly prompted the minister of Justice (Malami) to hire the two Nigerian lawyers - Oladipo Okpeseyi, a Senior Advocate of Nigeria (SAN), and Temitope Adebayo.
Both lawyers were said to have worked for Buhari's Congress for Progressive Change (CPC), a legacy party of the All Progressive Congress (APC).
Monfrini, however, denied the allegations that he asked for 20 percent.
"I never had the audacity to claim for additional fees. This figure of 20% is simply invented. I didn’t reject any proposal made by Mr. Malami since my fees were already paid a long time before Mr. Malami’s appointment as attorney general," Monfrini said in an email sent told The Cable.
"The repatriation of the $321 million was not completed by me. It’s a matter which is normally dealt between governments and which doesn’t entail the engagement of lawyers. I have no idea of the whereabouts of these $321 million.
"I know that they have been restituted to Nigeria by the Swiss government a few months ago. On the other hand, I don’t know why it took about three years for the two governments to agree that said restitution should be monitored by World Bank since this concept was created by me some 15 years ago."
On October 26, 2017, Malami confirmed that Nigeria had concluded negotiations with Switzerland on the return of $321 million recovered from the late Sani Abacha family, adding that the loot would be repatriated within weeks after the two parties sign a Memorandum of Understanding (MoU).
Nigeria and Switzerland signed the MoU in December 2017 at the Global Forum on Assets Recovery meeting held in Washington, United States.