Spanish cycling ace Alejandro Valverde may face doping charges after Italian authorities on Wednesday said DNA collected at last year's Tour de France matched blood seized in the infamous Operacion Puerto.
Valverde, 28, has been trying for three years to shake off allegations of involvement in the case.
The evidence announced Wednesday could pin him down, experts say.
Two-time world road race runner-up Valverde, twice a winner of the ProTour, was summoned by the Italian Olympic Commitee (CONI) on Wednesday.
He will be questioned by CONI prosecutors on Monday.
The DNA in question emerged from a blood sample taken during the Italian stage of the 2008 Tour de France.
It matched plasma confiscated from Eufemiano Fuentes, the doctor at the centre of Operacion Puerto, CONI said.
Valverde has a case pending with world sport's top court, the Court of Arbitration for Sport (CAS) in Lausanne.
The World Anti-Doping Agency (WADA) appealed to the CAS against his 2007 Operacion Puerto acquittal by the Spanish cycling federation.
CONI on Wednesday sent its findings to WADA and world cycling's ruling body UCI.
In 2007 UCI prevented Valverde from taking part in the 2007 world road race championships because of his association with the probe, but Spanish doping authorities went on to clear him.
The three-year-old Puerto probe uncovered evidence of links between Fuentes and some 200 professional athletes including 34 cyclists.
2006 Giro d'Italia winner Ivan Basso of Italy received a two-year ban after admitting in 2007 he was planning to use blood doping provided by Fuentes at the 2006 Tour de France.
Germany's first Tour de France winner, Jan Ullrich, retired in 2007 after allegations he had used Fuentes' services.
Ullrich, who won the Tour in 1997, a year before the late Marco Pantani and two years before Lance Armstrong began a seven-year reign, insisted he was clean.
