It looked like a clear victory.
Daniel Mesfun from the African country of Eritrea crossed the Cleveland marathon finish line with a time of 2-hours, 16-minutes and 33-seconds.
His victory is now being contested.
Other participants allege that Mesfun wore a shirt that covered his bib, that identified him as a runner, throughout the race.
They say he only removed the shirt towards the end of the race, confusing other contestants on whether or not he was in the marathon or half-marathon.
Only 22-seconds separates the top two finishers.
Mesfun is seen on video waving the alleged shirt around his body in celebration.
Organizers of the 41st annual marathon release a statement saying, "A few runners are contending Mesfun's bib was not visible through the duration of the race. We will make a determination and certify results in a few days after we complete a through review."