Denis Pitner, a Croatian tennis umpire suspended from officiating last August after a corruption inquiry, worked as a linesman at the 2015 United States Open despite that suspension.
In a statement, the United States Tennis Association, which operates the Open, attributed the extraordinary situation to “a flaw in our process” and explained that Pitner had picked up his credential before the U.S.T.A. received notification of the suspension.
Pitner was suspended under the International Tennis Federation code of conduct after an investigation by the sport’s internal watchdog, the Tennis Integrity Unit.
The suspension was not revealed publicly until a Guardian newspaper investigation earlier this month.