A Spanish judge has said he suspected from the start that Islamic militants were behind the Madrid bombings, not the militant Basque separatists Eta.
Baltasar Garzon is an expert on Eta and al-Qaeda
Judge Baltasar Garzon told the parliamentary commission into the 11 March attacks he did not believe it when the government said it was Eta.
The Popular Party, in power at the time, initially insisted Eta was behind the train bombs that killed 191 people.
But Judge Garzon said the nature of the attacks seemed to him like al-Qaeda.
Judge Garzon said the scale of the attack and the co-ordination of planting bombs on four commuter trains bore the hallmarks of a group like al-Qaeda.
He said he told a friend on the morning of the attacks: "This is Islamic terrorism."
Two senior policeman he spoke to on 11 March also backed the theory that Islamic militants were to blame, he said.
Judge Garzon said he was also swayed by forceful denials by radical Basque leader Arnaldo Otegi.
"[Otegi] is not in the habit of lying when it comes to admitting responsibility," he said.
Judge Garzon is investigating suspected al-Qaeda cells operating in Spain.
The Madrid attacks were the worst of their kind in Europe
In 2003, he called for the arrest of 35 men, including Osama Bin Laden, for their alleged involvement in the 11 September attacks on the US.
He is one of a number of people whose evidence to the commission supports arguments that the conservative Popular Party government rushed to blame Eta out of fear that a Muslim link could cost it the general election due three days later.
The government had gone against popular public opinion by supporting the war in Iraq and later sending troops to the region.
In the event, the Basque theory was soon discredited and the conservatives were voted out.
Last week a bomb disposal expert said the then interior minister, Angel Acebes, told reporters that the explosive used was favoured by Eta, before it had been identified.
Another officer said the minister had still blamed Eta after police had identified Islamic militants as prime suspects.
The government finally stopped blaming Eta after a mobile phone found with an unexploded bomb was traced to a Moroccan-run shop.
More than 20 people have been accused of playing a role in the 11 March attacks. Sixteen of them are of Moroccan origin.
The commission is charged with establishing whether more could have been done to prevent the bombings and what impact they had on the 14 March election.