Zimbabwean journalist and author Heidi Holland, acclaimed for her penetrating portrait of President Robert Mugabe, was found hanging in her Johannesburg garden on Saturday, police said.
"She was found by her gardener this morning and he called the police," said police spokeswoman Katlego Mogale.
Holland, believed to be 64, authored "Dinner with Mugabe", a book based on her interviews over 30 years with Mugabe chronicling his rise to power and his transformation from a freedom fighter to an authoritarian ruler.
The veteran ruler has led Zimbabwe since its 1980 independence from Britain and has been accused by critics of stifling human rights and ruining the southern African nation's once-model economy.
None of her possessions were missing, Mogale said.
Tributes from South Africa and Zimbabwe poured in on social networks late Saturday.