"We confirm there is such a report and there is such a probe," said Zimbabwe Anti-Corruption Commission spokeswoman Phyllis Chikundura who declined to provide further details.
In November 2017, Robert Mugabe fired then-vice president Emmerson Mnangagwa, a move that was seen as opening the way for his wife's succession. A few days later the military took control of the country, leading to Mugabe's resignation on November 21.
Mnangagwa was sworn in as president days later and both Robert and Grace have kept a low profile since their spectacular reversal of fortune.
During the height of the upheaval, students at the University of Zimbabwe boycotted their end of term exams to call for Grace to be stripped of her PhD and Robert to be stripped of the presidency.
Grace was routinely accused of extravagant spending on luxury clothes and international travel, and of involvement in corrupt land deals.
Dubbed "Gucci Grace", "The First Shopper" or even "DisGrace", she showed her political mettle in 2014 with her ruthless campaign against then Vice President Joice Mujuru, who was then a contender to succeed her husband.
A similar briefing campaign — conducted both publicly and behind the scenes — against Mnangagwa is widely seen as having led to her husband's downfall.