SPAIN (Agencies) Marta Domínguez, the most successful female athlete in Spanish history, was arrested on Thursday for allegedly belonging to a gang that distributed illegal substances to athletes. Another 13 people were detained in Operación Galgo (Operation Greyhound), including sports doctors, trainers, representatives and other elite athletes. The 3000 m steeplechase world champion was taken in for questioning -which lasted 8 hours- and released on bail. Anabolic steroids, hormones, bags of blood, documents relating to doping and other material used for blood transfusions were among the material seized in raids on 15 different residences during the operation. The Spanish Athletics Federation, of which Domínguez was a vice-president announced this morning that she had been suspended pending further investigation.