Belgian police have offered a $2.6 million reward for information that will help them track down a man who stole an estimated $28 million worth of diamonds from an Antwerp bank last week, The Associated Press reports.

The stolen diamonds weigh 120,000 cts. and includes some very unusual stones, police reportedly said.

The man reportedly broke into open safety deposit boxes in an ABM Amro bank in the city’s diamond quarter, the AP reports.

Police are unsure how he did it but believe he may have carefully planned the robbery, becoming one of several trusted diamond traders given an electronic card to access the vault, the AP reports. The suspect had been a regular customer at the bank for the past year, giving the name Carlos Hector Flomenbaum from Argentina.

They now believe that the suspect was using a false identity because a passport in that name was stolen in Israel a few years ago, the AP reports.

Belgium authorities released a composite photo of a gray-haired man, 6 foot 3 tall and aged between 55 and 60. They said he speaks English with an American accent and often wears a baseball cap, the AP reports. Authorities are asking that anyone who got to know him during his time in Antwerp to come forward.

The bank discovered the theft on March 5, believing that someone took the stones that Monday morning or the previous Friday from a vault used by pawnbrokers and diamond cutters, the AP reports.

Police did not say why they had waited over a week before making the theft public, nor did they mention who had put up the reward money, the AP reports.

The diamonds will be difficult to sell on world markets, Philip Claes, spokesman for the Antwerp Diamond Council, reportedly said. He told Belgium’s RTL-TVI television network the haul included both cut gems and rough diamonds which cannot be sold without certificates of origin to show they have not come illegally from war zones.

JCK