The ongoing Spanish doping investigation, Operación Puerto, entered a new phase on Wednesday when a Madrid magistrate's court lodged an appeal against the case's dismissal.

The inquiry, which came to light in May 2006 when police raids discovered an alleged blood-doping network run by the Madrid-based Dr Eufemiano Fuentes, considered to be the mastermind behind the network, was thrown out due to a lack of evidence.

The probe uncovered an alleged doping network said to involve 58 cyclists out of some 200 athletes being treated by the doctor. Nonetheless, on Monday presiding magistrate Antonio Serrano ruled that there was no case to answer.

Technically, the case could also not go the full term because at the time there was no Spanish anti-doping law at the time of the alleged infractions. Spain only recently followed France and Italy in introducing a law against doping, and the use and distribution of banned substances. The law went into effect in November 2006.

The magistrate ruled that five people at the center of the affair, including Fuentes, were cleared of any involvement. On Wednesday, however, another magistrate filed a motion seeking a higher court’s opinion in the case.

While the Spanish criminal matter may or may not be resolved, anti-doping officials at the UCI and the World Anti-Doping Agency have said that their investigations would continue, since the ruling had nothing to do with the regulatory authority granted both agencies under the World Anti-Doping Code.

Revelations implicating top cyclists had led to several yellow jersey favorites being suspended by their teams two days prior to the 2006 Tour de France.

Ivan Basso (then of CSC) 1997 Tour winner Jan Ullrich (then of T-Mobile) were among nearly dozen riders pulled out of the race for allegedly being directly or indirectly involved in the affair.

Both Basso and Ullrich were fired by their teams. Basso, last year's Giro d’Italia, was later cleared of any wrongdoing by the Italian sports authorities due to what they claimed was a lack of evidence. Basso has since signed with the Discovery Channel squad and Ullrich has retired.