Canadian authorities suspect al Qaeda members in Iran provided information to alleged plotters . Iran has denied the alleged terrorist conspiracy could have been plotted from its territory . Several weeks later the cell that carried out the attack attempted to blow up a bridge on the Madrid-Seville high-speed train line . Western intelligence has long thought any al Qaeda operatives in Iran are under strict surveillance . Al Qaeda 's interest in Iranian intelligence underscored the death of Osama bin Laden .
Canadian authorities suspect al Qaeda members in Iran provided information to alleged plotters . Iran has denied the alleged terrorist conspiracy could have been plotted from its territory . Western intelligence has long thought any al Qaeda operatives in Iran are under strict surveillance . Al Qaeda 's interest in Iranian intelligence underscored the death of Osama bin Laden .