` It is not a ``El Mundo`` exclusive ``lunacy``. ``The Guardian`` also thinks that the issue is credible. I hope this will end this nonsensical debate about the quality of the sources.  ``the actual investigation of the origins and ramifications of the attacks has proceeded at snail's pace. Several suspected terrorists were blown up - or blew themselves up - in an apartment on the outskirts of Madrid days after the bombing, which certainly made things more difficult. In addition, it is hard to envision anyone among those who died or those who have been arrested having enough planning skills and technical sophistication to have organised the highly synchronised attacks and having set up the sophisticated explosive devices that were detonated with cell phones. `` `