A Spanish judge rejected a request by anti-doping authorities to hand over as many as 200 blood bags belonging to cyclists and other athletes, ordering that they be destroyed instead.

The ruling by Judge Patricia Santamaria came after a trial of Eufemiano Fuentes, a sports doctor who gave transfusions to Tour de France riders to boost their performance. The bags were found in his possession, and the World Anti-Doping Agency was among groups looking to identify the athletes involved in so- called blood-doping, which is banned in sports.

Montreal-based WADA wanted to take disciplinary proceedings against athletes who haven’t faced sanctions as a result of a 2006 investigation in Madrid called “Operacion Puerto,” or Operation Mountain Pass. As few as a dozen of the 58 cyclists that police linked to the doping ring, and no one from other sports, have received bans.

Tennis - Murray: Puerto case 'biggest cover-up in sports history?'

Andy Murray has tweeted his disbelief after a Spanish court reached its verdict on doctor Eufemiano Fuentes.

Fuentes, the central figure in the Operation Puerto case, a drugs scandal with possible repercussions across all sports, was sentenced to a year in prison - but the judge presiding over the case also ruled that all evidence in the case was to be destroyed, damaging the chances of understanding the operation's scale and breath.

Fuentes - who is unlikely to be jailed because sentences under two years in Spain are usually suspended - was convicted for crimes against public health, barred from practising sports medicine for four years and fined.

However, judge Julia Santamaria's decision not to release case evidence, including bags of blood seized in police raids, to anti-doping authorities for further investigations hit hopes that the case would unmask athletes caught up in the doping programme.

Murray, writing on Twitter, asked whether the verdict represented the biggest cover-up in sports history.

"operacion puerto case is beyond a joke... biggest cover up in sports history? why would court order blood bags to be destroyed? #coverup"

The Spanish anti-doping agency has said that it would appeal the judge's ruling to destroy the evidence.