PARIS — A 28-year-old Belgian man has apologized after hurling a plastic bottle at former world champion Mathieu van der Poel during Sunday’s Paris-Roubaix race, an act that led to a criminal investigation by French authorities.

In an email released by Flemish daily Het Nieuwsblad on Wednesday, the man from Waregem expressed regret for what he described as a “stupid and dangerous” moment of impulsivity.

“I am so happy that he crossed the finish line first on Sunday, despite my stupid action,” he wrote. “A water bottle was in the grass. I picked it up and threw it when he passed. Without thinking. Half a second later, I realised how stupid and dangerous it was.”

The man, who admitted to having “drunk a lot” that day, said he has felt ashamed for days after the incident and extended an apology to Van der Poel, other riders and cycling fans.

Dutch Alpecin-Deceuninck rider Van der Poel was struck in the face by the bottle while riding solo at high speed over a cobbled section with about 20 miles remaining. Despite the blow, he went on to win the race for the third consecutive year.

French prosecutors opened an investigation into “violence with a weapon” shortly after the incident. The Lille public prosecutor, Carole Etienne, said authorities were working to identify and arrest the suspect on Tuesday.

The International Cycling Union labeled the act “unacceptable behaviour.”

“Such behaviour cannot be tolerated in the context of a cycling event,” the UCI said in a statement. “We express our support for the rider and will explore all legal avenues to ensure such actions are duly and severely punished.”

Van der Poel called the act dangerous and urged tougher consequences for spectators who threaten rider safety.

“It’s not normal,” he told reporters. “It was a full bottle. … It was like a stone hitting my face. This is really something we have to take legal action against.”

His team said it planned to file a formal complaint, describing the incident as part of a broader pattern of dangerous fan behavior often linked to excessive alcohol consumption.

“It jeopardizes the safety of our riders, overshadows the enjoyment and reputation of genuine cycling enthusiasts, and diverts attention from the sporting achievements,” the team said.