Police are hunting thieves who snatched £250,000 of diamonds from the Spring Fair on Sunday.
The 20 clear-cut gems were inside a box within a locked cabinet on the stand of an unnamed Belgian company. The theft occurred at lunchtime while the stand was well manned.
Det Insp Iain Grant of West Midlands Police said: “At the moment it remains a mystery how a thief could have access to the diamonds. There was no damage to the lock on the cabinet and there were three members of staff on duty at the stall, who didn’t see anything. We are investigating all potential avenues of inquiry.”
The robbery is almost identical to one that happened a year ago. At Spring Fair 2007 £500,000 worth of diamonds were lifted from a stand on the Sunday, at the same time. Police say there is a possibility that the two thefts are linked. They have not caught anyone in connection with the first despite a £20,000 reward being offered.
Anyone with information about the robberies can call the police on 0845 113 5000.