Three men posing as an art teacher and two students stole paintings worth about $2 million.
According to Reuters, the works by some of South Africa's most celebrated artists were stolen off the walls of the Pretoria Art Museum in a brazen daytime robbery.
The stolen works were: "Cat and Petunias" from Maggie Laubser, Hugo NaudÃ©'s "Hottentot Chief", "Eland and Bird" from J.H. Pierneef, Gerard Sekoto's "Street Scene" and "Fishing Boats" from Irma Stern.
One of the stolen works, Fishing Boats by Irma Stern
The report says the three thieves paid an entrance fee of just over $1 each on Sunday and asked museum staff to direct them to the six works of art, which happened to be among the most valuable paintings on display.
Workers at the museum in South Africa's capital said it seemed as if the thieves had a shopping list. They then produced weapons, tied up a museum worker and took the art works out of the building, a city spokesman said on Monday.
"They exactly knew what they wanted and they were almost certainly commissioned to steal these paintings," said Pieter de Necker, a spokesman for the Pretoria.
They left behind one painting by Stern called "Two Malay Musicians", valued at about 12 million rand ($1.4 million), because they could not fit it into their getaway vehicle in time with security guards closing in.