A group supporting victims of crime in South Africa says it will legally challenge a controversial Foreign Ministry decision to grant immunity to Grace Mugabe, a move which allowed the wife of Zimbabwe’s president to leave the country without standing trial for an alleged assault on a young model.

AfriForum's chief Kallie Kriel said Monday that the civil rights organization was preparing a court injunction to set aside the decision to grant diplomatic immunity to Grace Mugabe after she reportedly assaulted Gabriella Engels, a 20-year-old model, with an electrical extension cord at a hotel in Johannesburg.

“We are going to ask the court to say that the decision to grant immunity is unlawful because our legislation says that diplomatic immunity cannot apply in serious crimes, and violence is part of that,” said Kriel.

The rights campaigner also said that Grace, the wife of Zimbabwe’s ailing leader Robert Mugabe, was in South Africa for medical assistance, adding that she could not enjoy diplomatic immunity during the stay.

“We believe that the diplomatic immunity should not have been granted,” Kriel said, adding, “She had been here for medical assistance with regards to her foot and therefore diplomatic immunity does not apply.”

Grace flew out of South Africa in the early hours of Sunday despite being sought by police for the assault on Engels, which left the young model with cuts on her forehead and on her head that required stitching. That had prompted the model to file an assault charge against Mugabe.

South Africa’s Foreign Ministry said later on Sunday in a statement that it had granted Grace Mugabe immunity, although it acknowledged that the decision “was not an easy one to make” and came after “careful consideration of all the relevant factors.”

AfriForum said, however, that seeking diplomatic immunity for Mugabe was an “afterthought” and that the Foreign Ministry’s decision was in line with a regional “culture of impunity.”

The group vowed to help Engels seek justice, adding that even if the court did not accept to overrule the immunity, the effort would still be positive as it could stop Grace Mugabe from visiting South Africa again.

“In the worst case scenario, if we get to a situation where she cannot come to the country any more, I think that will be a positive step,” said Kriel, adding, “But the first prize is to make sure she is being prosecuted.”