The 95-year-old, who died in Singapore, ruled Zimbabwe with an iron fist until toppled by a military coup in 2017.
The deposed leader said he has been given $467,000 and two houses, which he claims is not enough.
Mnangagwa and Grace Mugabe have been seen as political rivals since he was removed from his post as vice president prior to the coup that led to her husband's resignation.
Martha O' Donovan, who grew up in New Jersey, was arrested in November after allegedly insulting Robert Mugabe online a few weeks before he was ousted in a coup.
Zimbabwe's Robert Mugabe, untouchable for decades and a hero of African independence, is out. Who's next?
Mnangagwa, who was inaugurated as president on Friday, has promised to compensate white farmers dispossessed of their land.
Harare was a happy place to be on Tuesday.
The 93-year-old leader stepped down after a week of protracted negotiations with the military.
A military takeover seems to herald the last days of Africa's oldest ruler, whose tenor has seen Zimbabwe fall into economic despair.
General Constantino Chiwenga warned of military intervention to back independence figures after President Robert Mugabe purged his prominent second-in-command.
A manhunt is underway after the first lady was heckled at a rally.
Robert Mugabe fired his deputy on Monday, paving the way for his wife Grace to succeed him.
Zimbabwe created a cybersecurity ministry in October, in a move critics say was designed to muzzle opposition to the 93-year-old president.
A report that Grace Mugabe donated used underwear to party activists is the latest in a series of embarrassments caused by the first lady.
The African leader gave Trump both barrels for threatening to "totally destroy" North Korea.
The Zimbabwe delegation did not look particularly thrilled by Trump's 41-minute monologue.