A Kurdish refugee turned Cambridge University professor who was awarded math's most prestigious prize in Rio de Janeiro on Wednesday had the gold medal stolen from him just minutes later, organizers said.
Caucher Birkar, 40, was one of four winners of the Fields award, which is seen as equivalent to the Nobel prize in mathematics. Crime-ridden Rio was the first Latin American city to host the prize-giving ceremony.
The International Congress of Mathematics, which organized the event, said it "profoundly regrets the disappearance of the briefcase of mathematician, Cauchar Birkar, which contained the Fields medal."
Security camera images were being examined and police were investigating, the organizers said in a statement.
According to TV Globo, Birkar left the medal along with his wallet and phone in a briefcase on a table at the convention center. He alerted security staff when he noticed the case was missing and they later found the case, but the medal and wallet were not there.
The International Mathematical Union, which gives the award to between two and four people every four years, described the medal as made of 14 karat gold and measuring 2.5 inches (6.35 cm) in diameter.