The Swiss Alex Wilson ran the 100 meters in 9.84 seconds at a non-international athletics meeting in Marietta / USA on Sunday.
This time would mark a new European record, but the confirmation raises questions.
His time was registered by the International Federation, but many observers stressed the arguable nature of the situation.
"We know 100 percent that it is not possible," tweeted the respected American trainer Rana Reider.
Doubts were also expressed as to whether a so-called Start Information System was used at the meeting.
The 30-year-old Wilson achieved his time as part of his preparatory training camp for the Summer Olympics starting on Friday with a tailwind of 1.9 meters per second.
Shortly afterwards he won the 200 meters in a Swiss record time of 19.89 seconds (1.8 m / s).
The Swiss Blick wrote of a “record flood”.
Wilson's personal 100 meter best time was 10.08 seconds until Sunday, and this season the Jamaican native had a top time of 10.38 seconds to date.
The recognized European record stands at 9.86 seconds, held by the Portuguese Francis Obikwelu and the French Jimmy Vicaut.
The European Athletics Association will be responsible for validating Wilson's time as a European record.