The Italian branch of the Anonymous hacking collective has defaced the homepage of Italian Olympic 50km race walk champion Alex Schwazer, who was disqualified from London 2012 for testing positive for performance-enhancing blood booster EPO.
Featuring a Guy Fawkes' mask which says "no to doping", the website also carries a statement by the syndicate which condemns the use of banned substances.
"Doping kills sport. Doping kills life," said the hacktivists. "Anonymous Italy condemns the doping practice in sport.
"Dear Alex, besides being an athlete you are also a carabinieri [a member of the Italian army who has civil responsibilities]. You should not have committed this mistake as your life, your job, your sport bring too much responsibility for us, your family and your people.
"We, Anonymous, join those who fight and work to "clean" the sport of the doping plague."
Schwazer, who has been suspended by CONI, the Italian Olympic Committee, had been one of Italy's big medal hopes in the 50 km race walk - having won gold at Beijing 2008, breaking the Olympic record by more than a minute.
However he tested positive for EPO, a supplement which increases the aerobic capacity of the body's blood cells, and was banned before even reaching London.
In a televised interview with Italian public broadcast RAI, Schwazer said he obtained EPO on his own, and used it because he felt immense pressure to win again.
Sobbing during the interview, Schwazer insisted that he won gold at Beijing without the assistance of drugs, adding: "I wanted the gold again at all costs."