Initial toxicology tests on Belgian cyclist Michael Goolaerts, who died during a race earlier this year, have come back negative, the state prosecutor in charge of the case told AFP on Tuesday.
"There is nothing special," Remi Schwartz said.
"The results are negative. As of today we have nothing that suggests it was anything other than a sudden death from a heart attack."
Goolaerts, 23, was found unconscious at the side of the road after racing along one of the famous cobbled sections in the Paris-Roubaix race on April 8.
Schwartz added: "There was no alcohol, no drugs and no medication other than what was administered (in hospital)."
An autopsy confirmed the Belgian suffered a heart attack before crashing in the early stages of the cycling one-day classic.
Belgian cyclist Michael Goolaerts died after being found unconscious at the side of the road during the Paris-Roubaix race on April 8