Sergio de las Heras was 28 years old and lived in Alcalá de Henares. According to his parents, he was reserved and private. He was planning to get married in a few months’ time and buy a flat in Guadalajara. “Dad, I’ve found a nice flat. Will you give me the money you promised me,” he had asked his father. He normally drove to Madrid, but for the last two weeks he had been taking the train so that he could check over some papers on the way. His father did not want to know where his journey ended.
11 March 2004 fell on a Thursday. Early that morning, a number of terrorists with links to Al-Qaeda planted thirteen bombs on four suburban trains covering routes running through Madrid. Ten of the bombs exploded between 7.37 and 7.39 am, when the trains were at Atocha, El Pozo and Santa Eugenia stations and alongside Calle Téllez. 191 people were killed in the attack and around 1,500 were wounded. It was the deadliest terrorist attack in Spanish history. On 3 April 2004, agents from the Special Operations Group (GEO) were about to enter an apartment in Leganés where the perpetrators of the attacks were believed to be hiding when the terrorists detonated twenty kilograms of explosives in an act of collective suicide. The blast killed one of the officers, bringing the total number of people killed by the 11 March killers to 192.