A doping sting operation in Spain has led to the arrest of some high-profile sporting figures as well as the reappearance of a doctor known for his vast doping knowlegde.

Madrid – Spanish doctor Eufemiano Fuentes, who was at the centre of the biggest cycling doping scandal so far in 2006, was thought to have retired from the world of sports.

“I was lynched,” Fuentes told the daily El Mundo in May. “A lot of harm was done to me, and it cannot be repaired. I am starting from zero as a family doctor. I don't have any interest in sports.”

Fuentes may not have honoured his pledge, as he has now been detained in another major doping probe.

The Canaries-based practician is among 14 suspects charged with being part of a doping ring that allegedly supplied athletes with banned substances.

The suspects include the 2009 steeplechase world champion Marta Dominguez.

Fuentes may not really have retired as a sports doctor, but remained involved behind the scenes, advising sports professionals in exchange for lucrative payments, police suspect.

The detainees allegedly used forbidden methods such as transfusions of athletes' own blood as well as forbidden substances such as the blood booster erythropoietin (EPO) and anabolic steroids, according to police.

Fuentes, however, has consistently protested his innocence to doping charges.

Fuentes had already been linked with a huge doping scandal in 2006, when the so-called Operation Puerto targeted cyclists, officials and doctors over blood doping.

Famous riders such as former Tour champ Jan Ullrich were sacked by their teams, while Alejandro Valverde and Ivan Basso served competition bans.

Fuentes – allegedly known within the doping ring as “Asterix” – was not sanctioned, because Spain had not yet introduced its current anti-doping legislation. However, the case has been reopened and the doctor now faces trial.

Fuentes – a trained gynaecologist and former athlete – was among a group of doctors who put in place a programme called biological following, which contributed to the success of Spanish athletics in the early 1980s.

At the time, Fuentes defended the use of blood transfusions and anabolic steroids to help sports professionals recover the strength they lost in training and contests.

Fuentes had begun working for the Spanish Athletics Federation (RFEA) already in the 1970s. The athletes he prepared included his wife, Cristina Perez. When she tested positive for doping in 1988, Fuentes had to leave the federation.

Documents discovered in the Operation Puerto indicated that Fuentes may have been involved with athletics in recent years as well. Some even claim that he has cooperated with the most powerful Spanish football clubs. – Sapa-dpa