The devastating terror attacks saw 10 bombs explode almost simultaneously at three stations during the early morning rush hour. Police believe devices were loaded onto the four trains as they passed through Alcala de Henares station en route for Madrid. Two explosions in separate carriages on a double-decker train at El Pozo station, just outside Atocha, killed at least 70 people and injured scores of others.
Investigators believe each device was set off by mobile phone. Police also carried out controlled explosions on three other unexploded devices found at the station.
The blasts hit three days before the last elections, which the governing centre-right Popular Party had looked set to win. But the then government’s insistence that ETA planted the bombs quickly backfired when detectives found evidence showing they were the work of radical Islamists and were linked to Spain’s backing of the U.S.-led invasion of Iraq.