Some of the alleged Islamist perpetrators had reportedly been under surveillance by the Spanish police since January 2003. According to the Spanish newspaper El Mundo, 24 of the 29 alleged perpetrators were informers and/or controlled by the Cuerpo Nacional de Policía, Civil Guard and Centro Nacional de Inteligencia ("National Centre for Intelligence") from the time before the attacks. Two alleged perpetrators were Guardia Civil and Spanish police informants. Cell phones used in the bombings were unlocked in a shop owned by a former Spanish policeman who is not one of those accused in connection with the bombings.