- operator " ▁from ▁later ▁getting ▁a ▁job ▁in ▁a ▁mine , ▁thus ▁gain ing ▁access ▁to ▁explos ives ▁and ▁bl ast ▁equipment . ▁ ▁Cont ro vers y ▁regarding ▁responsibility ▁ ▁Th ir teen ▁impro vised ▁explos ive ▁devices ▁were ▁reported ▁to ▁have ▁been ▁used ▁by ▁the ▁Islam ic ▁milit ant ▁group ▁that ▁was ▁responsible ▁for ▁the ▁bomb ing , ▁all ▁but ▁three ▁of ▁which ▁det on ated . ▁This ▁group ▁seems ▁to ▁have ▁had ▁very ▁ten uous ▁connection ▁with ▁al - Q a eda ▁but ▁with ▁the ▁aim ▁of ▁acting ▁on ▁its ▁beh alf . ▁Short ly ▁after ▁the ▁bomb ings , ▁the ▁group ▁was ▁completely ▁dis m ant led ▁by ▁the ▁Spanish ▁police ▁and ▁the ▁core ▁members ▁died ▁in ▁an ▁apparent ▁suic ide ▁explos ion ▁when ▁they ▁were ▁surrounded ▁in ▁the ▁nearby ▁town ▁of ▁Leg an és . ▁ ▁The ▁Madrid ▁bomb ings ▁have ▁led ▁to ▁the ▁sharp ▁political ▁and ▁social ▁differences ▁between ▁the ▁parties ▁in ▁Spain ▁being ▁acc ent u ated . ▁This ▁stands ▁in ▁sharp ▁contrast ▁to ▁other ▁large - scale ▁terror ist ▁attacks ▁such ▁as ▁those ▁in ▁New ▁York ▁and ▁London , ▁which ▁gal van ized ▁society ▁and ▁political ▁forces ▁towards ▁unity . ▁ ▁Spain ' s ▁political ▁division ▁is ▁exempl ified ▁by ▁the ▁accus ation ▁of ▁members ▁of ▁the ▁Partido ▁Popular ▁and ▁several ▁conserv ative ▁media ▁out lets ▁regarding ▁who ▁was ▁responsible ▁for ▁the ▁bomb ings ▁and ▁whether ▁the ▁attacks ▁were ▁for ▁political ▁gain . ▁Some ▁of ▁these ▁sources ▁initially ▁supported ▁the ▁hypothesis ▁that ▁E TA