what a senseless tragedy... those trains were packed with students...
as for the perpetrators, looks likely it was ETA
This is from a weblog --
1) It fits their MO. The bombs were made with small quantities, 8-12 kilos, of titadyne and what they're calling "compressed dynamite", which is the standard ETA technique.
2) The operation was within their capacity. To pull this one off you would need a bombmaker, who obviously never got anywhere near the trains; a couple of spies to spend a couple of weeks scouting the ground; a couple of people to transport the bombs; somebody running a safe house or two; and the actual bomb planters. While ETA is weakened and on its last legs, they've got the capability to pull off an operation of this size. They didn't need any specially trained pilots or suicide fanatics or the ability to beat airport security or huge amounts of money or international connections to commit such a massacre. All they needed was a hundred kilos of explosives, a skilled bombmaker, and 15-20 conspirators who may well have been working in several different cells.
3) It fits their recent history. The most significant clue is that on Dec. 24, 2003, they planted a bomb on a train in San Sebastian that was timed to go off when the train reached Chamartin Station in Madrid. Fortunately, the bomb planters were caught and the train was stopped at Burgos, where the bomb was discovered. The MO was exactly the same as in the Madrid bombings except that the bomb was larger, 50 kilos of titadyne, and hidden inside a suitcase rather than backpacks.
On Feb. 9 of this year, an ETA caravan was stopped by the French police near Bordeaux. They were carrying all sorts of weapons and explosives to be passed to a new commando inside Spain.
Then, on the last weekend of February 2004, the police stopped another ETA caravan at Cuenca with more than 500 kilos of explosives that were to be used for terrorist attacks in Madrid.
4) It fits in with the election campaign; general elections are to be held on Sunday, March 14, in two days. ETA has tried to disrupt general elections every time Spain has had them. Most famously, during the 1995 election campaign (April 19), they tried to assassinate Jose Maria Aznar, then PP candidate for Prime Minister. Aznar survived the bombing because of his armored limousine. A passer-by was killed.
5) The story that ETA "always gives a warning" before planting a bomb is simply false. They didn't give a warning when they loaded that bomb on the train in San Sebastian, for example. Or on July 14, 1986, when a bomb killed 12 people and wounded 50 in Madrid. Or on December 11, 1985, when a bomb in Madrid killed six people and wounded 19. Or on October 30, 2000, when a bomb killed three and wounded 66 in Madrid. Or on June 21, 1993, when a bomb killed seven people and wounded more than 30 in Madrid. Or on June 19, 1987, when a bomb killed 21 and wounded hundreds at the Hipercor department store on Avenida Meridiana here in Barcelona.
6) The behavior of Arnaldo Otegui, "leader" of Batasuna, the political branch of ETA. He denied ETA involvement in the bombings and blamed a group of "Islamic activists". Otegui was the first person to publicly float the hypothesis that this was an Al Qaeda bombing, though he didn't say Al Qaeda. Now, I personally don't believe anything Arnaldo Otegui says. You can believe what you want.
7) The facts are that the only other clues linking Islamic terrorists to the Madrid bombings are a) an e-mail from somebody saying he was from the Martyr Abu Hafs Al Masri Brigade, who has claimed to be behind everything from the UN bombing in Baghdad to the Marriott Hotel bombing in Jakarta to the blackout in the US Northeast, falsely, and b) a cassette tape with Koran verses on it found in a van linked to the bombing. That's awfully slim evidence. Also, the fact that Reuters jumped all over circumstance a) makes me extremely suspicious. Reuters is not at the top of my list of most trusted international news services.