Eufemiano Fuentes, the Spanish doctor currently on trial for doping offences in sport, says he can identify the patients he treated, who include cyclists, footballers and other sportspeople.
Fuentes and four co-defendants face charges arising from 2006's 'Operacion Puerto' which saw Spanish police uncover evidence of widespread doping in professional cycling. It began on Monday and is also expected to hear about illegal performance enhancement in other sports including tennis and football.
On Wednesday, the third day of his trial in Madrid, Fuentes said that he could, if asked, decipher the aliases fixed to bags of blood discovered by police during their investigation.
"I could identify them all, if they gave me a list I could say which person corresponds to each code, without a doubt," Fuentes said in comments reported by AS. "I am able to recognise any code that I am asked to."
Judge Julia Patricia Santamaría said she would not oppose him naming names, but would not ask him directly to do so.
According to El Pais, Spanish police discovered 200 bags of blood that Fuentes and his colleagues had kept frozen or refrigerated in Madrid apartments.
As doping was not illegal in Spain until 2006, the defendants are being charged with violating public health and safety laws. His defence is expected to be that he did treat athletes, but did so without endangering their health or breaking any laws.
Fuentes, an acknowledged expert on the use of EPO in sports, said that traces of the substance found in eight of 92 bags of plasma examined must have been already in the athletes' bodies before he took their blood.
"No product was ever added to the blood except legally established conservatives," he said. "That such small quantities were found could have no other explanation than that they were traces from a previous treatment."
Fuentes also said that he refused to treat Jesus Manzano, who could identify the doctor's former patients when he testifies later in the trial, as the former cyclist had taken recreational drugs which were dangerous to his health.
He also revealed that current Spanish Professional Cyclists Association (ACP) president Javier 'Pipe' Gomez had been a patient of his in the past. Just last December Gomez was named director of the Spanish government's Youth Sports Foundation (Fundación Deporte Joven).
Further names could emerge as the proceedings, scheduled to run until March 22, progress. Spanish authorities reportedly possess surveillance tapes showing a large number of as yet un-named sportspeople entering the building in which the bags of blood and related equipment were found.
Even if Fuentes' former patients are not identified in court, they could be later unmasked as Santamaria is to allow access to the blood samples used once the case has concluded. The judge has however decided against admitting evidence from Fuentes' computers as that would infringe his privacy.