THE GAMBLER WHO BEAT ROULETTE

FOR DECADES, CASINOS SCOFFED AS GAMBLERS DEVISED ELOBRATE SYSTEMS TO GAIN AN ADVANTAGE OVER THE HOUSE.THAT CHANGED AFTER AN UNASSUMING CROATIAN WON MORE THAN £1 MILLION OVER SEVERAL NIGHTS AT A LONDON CLUB. THE QUESTION FOR CASINOS, COPS AND A BLOOMBERG BUSINESSWEEK REPORTER WAS HOW, EXACTLY, HE DID IT 

- KIT CHELLEL

One spring evening, two men and a  woman walked into the Ritz Club casino, an upmarket establishment in London's West End. Security officers in a back room logged their entry and watched a grainy CCTV feed as the trio strolled past high gilded arches and oil paintings of gentlemen posing in hats. Casino workers greeted them with hushed reverence.

The security team paid particularly close attention to one of the three, their apparent leader. Niko Tosa, a Croatian with rimless glasses balanced on the narrow ridge of his nose, scanned the gaming floor, attentive as a hawk. He'd visited the Ritz half a dozen times over the previous two weeks, astounding staff with his knack for roulette and walking away with several thousand pounds each time. A manager would later say in a written statement that Tosa was the most successful player he'd witnessed in 25 years on the job. No one had any idea how Tosa did it. The casino inspected a wheel he'd played at for signs of tampering and found none.

That night, March 15, 2004, the thin Croatian seemed to be looking for something. After a few minutes, he settled at a roulette table in the Carmen Room, set apart from the main playing area. He was flanked on either side by his companions: a Serbian businessman with deep bags under his eyes and a bottle-blond Hungarian woman. At the end of the table, the wheel spun silently, spotlighted by a golden chandelier. The trio bought chips and began to play.

The Ritz was typical of London's top casinos in that it was members-only and attracted an eclectic mix of old money, new money and dubiously acquired money. Britain's royals were regulars, as were Saudi heiresses, hedge fund tycoons and the actor Johnny Depp. One cigar-chomping Greek diplomat was so dedicated to gambli he refused to leave his seat to use the toilet, instead urinating into a jug, so the story went.