Mnangagwa has denied any part in the atrocities and since his return to Zimbabwe after two weeks in hiding has been preaching democracy, tolerance and respect for the rule of law.
"The people have spoken. The voice of the people is the voice of God," he told thousands of supporters on Wednesday at the headquarters of his ruling ZANU-PF party.
However, the army's rough treatment of Mugabe loyalists - former finance minister Ignatius Chombo was hospitalised because of beatings sustained in military custody, his lawyer said - has not allayed concerns about Mnangagwa's real views of democracy.
"It was a very brutal and draconian way of dealing with opponents," Chombo's lawyer, Lovemore Madhuku, told Reuters.
Mugabe, the world's oldest serving head of state, resigned on Tuesday as parliament started to impeach him, a week to the day after the army stepped in to seize power.
Mnangagwa assured Mugabe he and his family would be safe in Zimbabwe when the two men spoke for the first time since Mnangagwa returned home this week, the state-owned The Herald newspaper reported on Friday.
