It gathered that the money was withdrawn from an account linked to Mrs Jonathan without leaving a trail.
But the money has been withdrawn without leaving a trail, it was learnt.
According to The Nation, the $175 million was found in the account of Pluto Property and Investment Limited, one of the firms linked to the ex-first lady.
The anti-graft agency discovered that the account was opened on November 30, 2013, by Pluto Property and Investment Company Limited with number 2110002238.
The company was registered on January 29, 2013, with RC 1092722, and the "strange" deposits came within 14 months of the registration.
The deposits are: 21/2/2014—$46,500,000; 24/2/2014 - $31,000,000; 31/3/2015 - $49,250,000; 1/4/ 2015 - $49,000,000.
"All the deposits were in cash, a development which showed that it was a pure case of money laundering," the newspaper quoted a source as saying.
"On the 21st of February, the account was reported to have recorded a cash deposit of $46,500,000 by the General Manager of Pluto Property and Investment Company Limited, Toru Wonyeng Ibuomo.
"Three days after (24th of February, 2014), another cash deposit of $31,000,000 was made by the same General Manager.
"Friday Davies made a cash deposit of $49,250,000 into the same account. The last tranche of $49,000,000 was deposited by Davies on Apri 1, 2015."
The EFCC is said to be trailing Ibuomo and Davies.
"We need the two depositors to assist in the ongoing investigation of the payments into the affected account.
"It is more curious when the bank details did not show evidence of withdrawals. Yet the whereabouts of the cash was unknown. We hope it is not a private banking arrangement to hide slush funds," the source said.
It was gathered that the EFCC will probe the likely roles of Mrs Jonathan in the suspicious account owned by Pluto Property and Investment Company Limited.
"In a matter before the Federal High Court, the ex-First Lady admitted that one of her domiciliary accounts was bearing Pluto Property and Investment Company Limited.
"We are investigating this $175.750million deposits and the extent of the involvement or relationship of the ex-First Lady with the funds. This is a fresh case; it has nothing to do with the $15.5million frozen by the EFCC," the source added.
The sum of $15.5million had earlier been traced to Mrs Jonathan, in which the EFCC placed 'No Debit Order' on four accounts the funds are deposited in.