Spain's anti-doping agency is looking into allegations that doping practices have spread beyond cycling and into football.
Ana Munoz, the director of Spain's anti-doping watchdog, said on Thursday the agency is "gathering information" about allegations by a former club president that Spanish team Real Sociedad had its players use performance enhancing substances.
Inaki Badiola told Spanish sports daily AS this week that before he took over as president in 2008 that the club had made "under-the-table payments" for six years for "medicines or products classified as doping" substances.
Badiola said Eufemiano Fuentes, the doctor allegedly at the centre of the Operation Puerto doping ring currently under trial in Madrid, "could have been" the supplier to the Basque club.
"But he himself (Fuentes) should confirm this in the trial going on right now for Operation Puerto," Badiola told AS.
That is unlikely since the trial has been limited to cycling and is hampered by the Spanish laws that were in force at the time of the investigation seven years ago when doping had not been criminalised.
Fuentes, Sociedad and its players, and another former club president that Badiola implicated in the supposed doping practices have all denied the accusations.
The club issued a statement saying that it can "guarantee since Dec. 20, 2008, there have been no irregular practices" at the club, adding that it would "actively collaborate" with authorities to "clarify the facts."
Former Sociedad president Jose Astizaran, who ran the club from 2001-2005 and is now the president of the Spanish football league, said that Badiola's charges are unfounded.
Astizaran added that Badiola had unsuccessfully taken him and others to court "on various charges" and that he had been cleared of all them.
Fuentes is one of five defendants being tried on charges of endangering the health of cyclists he allegedly performed blood transfusions on to boost their stamina before or after races, after raids by Spanish police in 2006 discovered evidence of so-called "blood doping."
The fact that only cyclists have been implicated in the Puerto case is a source of concern for many of sports' international governing bodies, above all the World Anti-doping Agency since even Fuentes has said he worked with athletes outside of cycling, without specifying.
The first indications that Fuentes could be linked with Sociedad came in court last Friday when prosecutors questioned another defendant about the letters "RSOC" that appeared on a piece of paper found in the police investigations.
After the proceedings closed for the day, Fuentes told Spanish media on his way out of court that RSOC sounded "like the name of a good wine".
The Puerto trial is scheduled to run until March 22.
The Spanish anti-doping agency has already asked for the judge to hand over any information that could assist in its investigation into doping activities when it issues its verdict.
Spain soccer coach Vicente del Bosque said that he had never seen "anything that made me suspect" a player was using a banned substance.
Badiola's accusations cover the years from 2001-07.
Numerous players played for Sociedad during that time, including Spain and Real Madrid midfielder Xabi Alonso, before signing with Liverpool.