At the tenth annual Steamboat Triathlon on Sunday, 28 participants experienced flat tires during the bike portion of the race because of thumbtacks that were strewn across the course. Because the course—specifically the area that traced Lake Catamount where the tacks were found—was inspected by race officials the night before, the tacks would have had to be placed during the early morning hours before the race began.

The race organizer, Boulder-based Without Limits, reported the incident to the Routt County Sheriff’s Office, which is currently conducting an investigation. “We’ve hosted triathlons for seven years, over 120 triathlons, and this is the first time we’ve seen this,” Race Director Lance Panigutti told Steamboat Today.

“I hope it’s not a local, in our case a Steamboat [resident]. We really take pride in outdoor recreation, [we’re] Bike Town USA,” Jim McCreight, a race sponsor and competitor, told CBS Denver.

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