• Evidence seized from Dr Eufemiano Fuentes was ordered to be destroyed • Tests could reveal identities of sports people involved in doping scandal

The World Anti-Doping Agency has taken custody of the 200-plus blood bags at the heart of the long-running Operation Puerto doping scandal, raising the possibility that the identity of those involved will be disclosed for the first time.

The blood bags were seized in 2006 when the Madrid-based Dr Eufemiano Fuentes was arrested and they remained in storage until he was put on trial seven years later for crimes against public health. He was initially given a one-year suspended sentence but the judge ordered that the blood bags should be destroyed.

However Wada and others appealed and in mid-June a Spanish appeals court cleared Fuentes but ruled that the blood bags should not be destroyed after all. Wada told the Guardian that it had now taken custody of the blood bags, along with world cycling’s governing body, and would consider its next move.

“We can confirm that following a judge’s order last week Wada and the UCI [Union Cycliste Internationale] proceeded to transport samples [of the blood and plasma bags] for storage in a Wada-accredited laboratory outside of Spain,” said a Wada spokesman. “Alongside the UCI we will now continue our investigation and will be considering all options open to us.”

In 2006 cyclists including Jan Ullrich, Ivan Basso and Tyler Hamilton were implicated in the scandal but the identities of the other sportspeople involved were never revealed.

During the 2013 court case Fuentes said of his clients: “They were sports people of all kinds. It could be a cyclist from a cycling team, a footballer from a football team, a tennis player or a boxer. There were also athletes.”

During the trial, Fuentes admitted he routinely kept frozen blood samples from his clients and used them for transfusions but claimed this was to protect them against anaemia and other harmful effects of low red blood cell levels.

The doctor, whose long career in sport included several stints working for professional cycling teams, denied any wrongdoing but he also admitted blood transfusions and tests were often done in hotel rooms, while blood samples were transported in a cooler bag kept cold with cans of Coca-Cola.

It remains to be seen whether Wada can identify whose blood is in the bags and whether it can take action as a result, given the 10-year statute of limitations on doping cases.

The 10-year threshold was passed just weeks before the Spanish court gave its ruling on Fuentes in June. In 2006, Spanish media reported that 99 blood bags analysed by the Barcelona anti-doping laboratory also contained high levels of EPO.