London: A tennis umpire who was suspended for a year as part of a betting investigation continued to work at tournaments, including last year's US Open, the US Tennis Association (USTA) confirmed Friday. Croatia's Denis Pitner, banned for a year in August after passing on information about a player's fitness to a coach and accessing a betting account that was used to place bets on matches, was a line judge at the US Open last September. He also officiated at last month's ATP Qatar Open at Doha, Pitner even posting a photograph of himself in the Qatari capital on his Facebook page.

A USTA statement said the national governing body was "shocked" to learn Pitner worked the tournament after being banned and has launched an investigation into how he managed to avoid having his credential revoked. "After learning within the last 24 hours that an official on the 'Do Not Credential' list may have worked at the 2015 US Open as a linesman, the USTA immediately investigated the claim," the statement said. "The USTA was shocked to find that this was in fact the case."