The Operación Puerto blood-doping affair, which erupted in May 2006, will be reopened, Madrid prosecutors said on Thursday.

Last year the case ground to a halt when a Spanish judge ordered it closed. Prosecutors asked an appeals court to review that decision, and a ruling is expected on Friday. The prosecutors' announcement, however, is a strong indication that the court will reopen the case.

The case began with a 2006 raid on the laboratory of Madrid gynecologist Eufemiano Fuentes. Investigators uncovered doping products, bags of blood and code names that appeared to link top athletes, including 60 cyclists, to a highly-organized system of doping, which relied heavily on blood transfusions.

A source linked to the Spanish government told AFP on Thursday that Madrid prosecutors claimed there could be new evidence on possible crimes concerning the obtaining, transport, preservation and identification of bags of blood seized during the inquiry.

So far, only Italy's top rider, Ivan Basso, has been formally sanctioned in the affair, although several riders have had their careers put on hold in the case and 1997 Tour de France winner Jan Ullrich was forced into retirement.

Dozens of other cyclists, including Alejandro Valverde, Tour de France winner Alberto Contador and Tyler Hamilton, have been linked to the case in the past.

The decision to reopen the case may satisfy demands from the UCI and World Anti-Doping Agency, both of which have requested the right to use thousands of pages of evidence generated by the investigation.

During the World Anti-Doping Conference in Madrid last November, former WADA president Dick Pound expressed frustration with the lower court’s decision.

"We still have evidence coming from the documentation that is available to the UCI that would indicate (whether any) particular cyclist might have been involved in Operación Puerto," Pound said. “The records and blood bags were coded and that code has been broken.

"The judge has said that none of the evidence, which is already available to all the parties, including us and the UCI, can be used for sports-sanctions purposes until the criminal case is entirely finished. We are sitting up there with a whole bunch of information that we know exists but you are prevented from using it."

At that same conference, UCI president Pat McQuaid met with Spanish sports minister Jaime Lissavetzky to discuss the use of Puerto documents in the governing body’s own investigation.

While the case began in May of 2006, it wasn’t until July of that year – on the eve of that year’s Tour de France – that the case had a major impact on cycling. Just days before the start of the Tour, several riders, including five members of the old Astana team, CSC’s Basso and T-Mobile’s Ullrich, were excluded from the race by officials who relied on the UCI ProTour rule that prevents any rider under current investigation from competing in a ProTour event.

Despite declaring their innocence, both Basso and Ullrich had their careers disrupted by the case. Ullrich continues to insist that he is innocent, but DNA tests linked nine bags of blood marked seized in the original Fuentes raids.

Fired by CSC, Basso went on to sign a deal with the U.S.-based Discovery Channel team, but left the team in May 2007 after Italian authorities reopened their own investigation - despite Spanish ojections - and demanded DNA samples from the 2006 Giro winner.

In a hearing in front of an Italian Olympic Committee panel, Basso admitted that he had worked with Fuentes, but only having gone as far as donating blood for storage, with an intent to dope. Basso, however, denied reinfusing the donated blood, saying the Puerto investigation prevented him from carrying out his plans. Nonetheless, Basso was given a two-year suspension. That suspension is set to expire in October.