Zimbabwe's first lady was sought by police for allegedly attacking a 20-year-old model at a Johannesburg hotel.
Zimbabwe's first lady Grace Mugabe flew home from South Africa on Sunday, state media said, ending a week of confusion over her whereabouts after she allegedly assaulted a model.
Mugabe, who had been sought by police for allegedly attacking the 20-year-old model at a Johannesburg hotel, was granted diplomatic immunity in the case by South Africa's foreign minister on Saturday.
"The minister has made the determination that the conferring of diplomatic immunity is warranted in this particular instance," the ministry said Sunday, citing a need "to maintain good inter-governmental relations" in the region.
"The decision was not an easy one to make," it added, saying that Foreign Minister Maite Nkoana-Mashabane had "agonised" over the case.
Grace Mugabe later flew home with her husband in the early hours of Sunday, public broadcaster ZBC reported.
The president had flown to South Africa on Wednesday to attend a two-day regional summit in Pretoria that began Saturday – which police said she had been expected to attend.
Grace Mugabe has not been seen since the allegations were made and failed to appear at the summit.
Anticipating her arrival, a group of protesters had gathered outside, some waving signs reading "Grace is a disgrace".
The 93-year-old president appeared to cut short his visit to fly home early, skipping the second day of talks among leaders of the Southern African Development Community (SADC).
South African police had said they were on high alert to make sure Mugabe's 52-year-old wife did not leave the country with officials reportedly weighing up whether to issue an arrest warrant.
The first lady is alleged to have assaulted Gabriella Engels with an electrical extension cable on August 13 at the hotel where the model was staying with Mugabe's two sons who have a reputation for partying.
Engels said she suffered deep cuts to her forehead and the back of her head and has opened a police case alleging assault with intent to do grievous bodily harm.
On Wednesday, Mugabe applied for diplomatic immunity although South African officials were not immediately available on Saturday to say whether or not her request had been granted.
Seen as a potential successor to her husband, Grace Mugabe is known for her temper.
In 2009, she successfully claimed immunity in Hong Kong after repeatedly punching a British photographer for taking pictures of her at a luxury hotel.
The alleged assault is a political headache for South Africa and Zimbabwe which are close neighbours with deep economic and historical ties.
Zimbabwean officials have declined to comment on the allegations against the first lady or her immunity claim.