Harare - Zimbabwe's main opposition, the Movement for Democratic Change party and pro-democracy groups have slammed First Lady Grace Mugabe over her alleged bashing of a model that she reportedly saw in the company of one of her two sons in South Africa.Grace allegedly assaulted a 20 year-old South African girl, Gabriella Engels over the weekend using an extension cord while her bodyguards looked on. Engels then made a report to the police.Although presidential spokesperson George Charamba did not answer his mobile phone, a report by Reuters - according to Al Jazeera - said that government sources confirmed on Tuesday that the first lady had returned home."Yes, she is back in the country. We don't know where this issue of assault charges is coming from," a senior government official told Reuters news agency on condition of anonymity.A second official also confirmed to Reuters that Grace had returned, saying "she is around now" and accused the news media of a plot to tarnish the first family's name.The First Lady’s sons, Robert Jnr and Bellarmine Chatunga, who are learning in South Africa, were known for notoriety and lavish lifestyles. The duo was recently kicked out of the apartment block in in the leafy Sandton suburb of Johannesburg after they reportedly engaged in "unacceptable behaviour" that left a security officer at the block with a broken leg and arm, prompting Grace to fly to South Africa to organise alternative accommodation for them.'Explosive and discourteous temperament'In the latest case, Grace allegedly used her medical trip to South Africa to also see her children at the Capitol 20 West hotel in Sandton when this incident happened. Her husband told a rally in Gwanda, about 500km south-west of the capital Harare, that she had gone to South Africa for a doctor’s review after her leg was injured in a freak accident at the Harare International Airport. Reports indicated that management at the hotel where Mugabe’s sons were staying immediately forced Grace and her children out of the hotel following the incident.Meanwhile, the MDC led by former prime minister Morgan Tsvangirai criticised Grace saying that her behaviour was not expected of a person of her status."Grace Mugabe is notorious for her explosive and discourteous temperament, particularly when she is dealing with people who she perceives to be powerless and under her authority. She has got a penchant for abrasive and thuggish behaviour that is completely inconsistent with the decorum and decency expected of a First Lady," said MDC spokesperson Obert Gutu.Zimbabwe's image "On more occasions than one (sic), Grace Mugabe has conducted herself like a bull in a China shop. She has to be brought to order and indeed, she has to appreciate that she is not a law unto herself," added Gutu.A local pressure group, Tajamuka, said it was riled by the First Lady’s action and was now calling for her immediate arrest wherever she would be seen."Grace Mugabe is now officially a criminal fugitive from justice. We call upon anyone who may know of her whereabouts to inform the nearest possible police station. In the same vein, we call upon every law loving citizen to do everything they can to help the Interpol to locate Grace Mugabe so that she may answer to charges of serious travesty of justice," said Tajamuka in a statement. The pressure group added that it had activated its structures worldwide “to be on the high alert and ready to assist to bring Grace Mugabe to justice”.The MDC official added that Grace had further tarnished Zimbabwe’s image.'I am not a hooker'"Zimbabwe's international standing has been severely dented by Grace Mugabe's criminal conduct in South Africa. Her act of violence is indeed, a gross and unmitigated diplomatic scandal. Grace Mugabe is a complete disgrace," said Gutu.An aspiring legislator based in the country’s second largest city of Bulawayo, Vimbaishe Musvaburi, said violence does not pay. "This whole situation is going to affect many people in both South Africa and Zimbabwe. Whatever form of violence should not be condoned, no one has a right to beat someone," said Musvaburi. "Noone has a right to discipline another person’s child in the absence of his or her parents and most of the Zimbabweans were embarrassed by Grace’s assault of Engels." Engels told 702 FM Live that she was not in love with any of Mugabe’s children, arguing that she was introduced to Bellarmine Chatunga by a mutual friend a day before she was assaulted."There is a rumour going round saying I am dating one of the Mugabe brothers I am not. Another thing I am not a hooker," said Engels.