Later in 2004, in his appearance before the parliamentary committee of inquiry, Juan Jesus Sánchez Manzano (the head of the TEDAX) stated that traces of nitroglycerine had been detected in the samples recovered after the bombings. He would later retract this statement before the investigating magistrate in charge of the case and emphasised that he was not an expert in explosives. The statement by Sánchez Manzano led supporters of the idea that ETA was involved in the bombings to question whether the explosive used in the bombs had been Goma 2 ECO. Nitroglycerine is not a component of Goma 2 ECO.