Eufemiano Fuentes, the Spanish doctor at the heart of one of cycling's biggest doping scandals, was found guilty of endangering public health and given a one-year suspended jail sentence at the end of the Operacion Puerto trial in Madrid.
But anti-doping organisations are set to appeal against the court's ruling that the 211 blood bags from 35 people seized in raids seven years ago and admitted as evidence be destroyed.
The decision led to an outcry around the world. The investigations had centred on cycling, although Fuentes claimed he had worked with runners, tennis players and footballers. Last night Britain's Andy Murray tweeted: "operacion puerto case is beyond a joke... biggest cover up in sports history? why would court order blood bags to be destroyed? #coverup."
The World Anti-Doping Agency director general David Howman said access to the evidence was what originally motivated WADA's involvement in the case and the pursuit of sanctions "against the cheats who used Dr. Fuentes' services" in cycling and other sports.
"The decision to order the destruction of the blood bags is particularly disappointing and unsatisfactory for ... the whole anti-doping community," Howman said in a statement.
He said WADA was reviewing options with its Spanish legal advisers before the May 17 deadline for appeals in the case, and would not make any further comment until that date.
The UK Anti-Doping chief executive, Andy Parkinson, added: "We are disappointed in the decision by the Spanish authorities. Dr Fuentes has admitted to having been involved in multiple prohibited doping activities, and linked with multiple unnamed athletes. It therefore cannot be right that these names will remain unknown and that no immediate action can be taken by the anti-doping community to protect our clean athletes."
Fuentes, who was also banned from working as a sports doctor for four years and fined €4,650 (£3,920), had been accused of running one of the biggest doping rings in world sport. The World Anti-Doping Agency (Wada) and Spain's anti-doping agency had hoped the blood bag evidence would identify drug cheats from cycling and other sports, but they have also been left dismayed at judge Julia Santamaria's ruling that the evidence be destroyed.
Former professional rider Jesus Manzano, who was a plaintiff in the case and had sought compensation from Fuentes and others for allegedly endangering his life, said the verdict was far too lenient. "It is shameful, I sincerely don't know why they bother charging a person in order to deliver a verdict like that," Manzano said.
Manzano had given testimony detailing a range of doping techniques used to boost performance, telling the judge in February that two of the drugs he was given were developed for use in animals. "Actovegin and Oxiglobin are for animals," Manzano said. "We used to joke in the team that some days you barked and others you mooed."
The court also sentenced former cycling team official Ignacio Labarta to four months in jail. It acquitted Yolanda Fuentes, Manuel Saiz and Vicente Belda. All had been charged with endangering public health, rather than doping offences, because Spain's anti-doping legislation was not in force in 2006.