Thief woos bank staff with chocolates - then steals diamonds worth £14m

A thief has evaded one of the world's most expensive hi-tech security systems, and made off with €21m (£14.5m) worth of diamonds - thanks to a secret weapon rarely used on bank staff: personal charm.

In what may be the biggest robbery committed by one person, the conman burgled safety deposit boxes at an ABN Amro bank in Antwerp's diamond quarter, stealing gems weighing 120,000 carats. Posing as a successful businessman, the thief visited the bank frequently, befriending staff and gradually winning their confidence. He even brought them chocolates, according to one diamond industry official.

Now, embarrassed bank staff in Belgium's second city are wondering how they had been hoodwinked into giving a man with a false Argentine passport access to their vaults.

The prime suspect had been a regular customer at the bank for the past year, giving his name as Carlos Hector Flomenbaum from Argentina. The authorities, who have offered a €2m reward for information leading to an arrest, now know that a passport in that name was stolen in Israel a few years ago. Although not familiar to the local diamond dealers, the conman became one of several trusted traders given an electronic card to access the bank vault. The heist, believed to have been more than a year in the planning, has astounded diamond dealers.

Philip Claes, spokesman for the Diamond High Council in Antwerp, said that the area had been fitted with a security system costing more than €1m. The lesson, he said, was that "despite all the efforts one makes in investing in security, when a human error is made nothing can help".

More than half the world's diamonds are traded in Antwerp's gem district. The maze of streets around the city's central station generates a turnover of £12bn a year. To serve this lucrative trade, banks have to accommodate clients who want to store diamonds overnight but withdraw them during the day. That means that special customers are given access to vaults.

Mr Claes said of the thief: "He used no violence. He used one weapon -and that is his charm - to gain confidence. He bought chocolates for the personnel, he was a nice guy, he charmed them, got the original of keys to make copies and got information on where the diamonds were.

"You can have all the safety and security you want, but if someone uses their charm to mislead people it won't help."

Police released a composite photo of a grey-haired man, 6ft 3in tall and aged between 55 and 60. He is said to speak English with an American accent and to have worn a baseball cap.

The bank discovered the theft on 5 March, believing that someone took the stones that Monday morning or the previous Friday from five deposit boxes in a vault used by diamond cutters. The authorities have not said why they waited for more than a week before making the theft public, nor have they said who had put up the reward money.

In fact Antwerp is no stranger to diamond thefts. In 2003 thieves prised open 123 safety deposit boxes in the city, finding so much booty they could only carry away $100m worth of diamonds, gold and jewellery.

That robbery was masterminded by an Italian gang, all of whom are now behind bars. But the diamonds they stole are still missing.