Johannesburg - Four William Kentridge artworks were stolen from the David Krut Projects art gallery in Parkwood on Saturday, Gauteng police said."A case of theft has been opened and we are investigating the incident," said spokesperson Sergeant Bongi Mdletshe.The gallery's manager Taryn Hackett said the robbery happened during working hours on Saturday afternoon."A couple came in to view the exhibition... I was suspicious of them and watched them leave."They didn't have any bags with them, so I think the guy might have slipped the prints under his shirt."We only noticed that four prints had been stolen on Monday and I reported it to the police immediately."Artinsure managing director Gordon Massie said the insurance company managing the artworks wanted to maximise publicity about the robbery "to stop the items moving".He said Artinsure had notified 2 500 people in the art industry about the robbery.