Spanish officials investigating the Madrid terror attacks provided little new information yesterday about who might have carried out the bombings, and gave conflicting interpretations of the evidence that emerged.
The Spanish interior minister, Ángel Acebes, said the Basque separatist group ETA remained the government's prime suspect in the bombings, in which at least 199 people have died.
Some Spanish antiterrorism officials said, however, that they questioned the government's seeming insistence on implicating the Basque group despite information that suggested the possible involvement of Islamic militants.
more...
http://www.nytimes.com/2004/03/13/international/europe/13TERR.html?ei=5062&en=8038eb31b836e873&ex=1079758800&partner=GOOGLE&pagewanted=print&position=
One theory I have heard is that the ETA may have tried to frame Al Queda for the bombings by leaving obvious arabic clues found in the van.
see this article on how blame game would affect Spanish elections.
Madrid bombings expected to influence Sunday's general elections in Spain
Madrid bombings expected to influence Sunday's general elections in Spain
12:43 PM EST Mar 13
MADRID, Spain (AP) - Depending on who voters believe is responsible for the Madrid bombings, Sunday's general election in Spain could turn into a referendum on Prime Minister Jose Maria Aznar's support for the Iraq war.
Spaniards reacted furiously last year when Aznar aligned himself with President George W. Bush and British Prime Minister Tony Blair to support the U.S.-led invasion. Aznar did not send combat troops but did dispatch 1,300 peacekeepers.
The Spanish government initially blamed the Basque separatist group ETA for Thursday's devastating train blasts in Madrid that killed 199 people and wounded more than 1,400. But now it is analysing a reported claim of responsibility on behalf of al-Qaida.
http://www.cbc.ca/cp/world/040312/w031262.html