Who Did It?

Confusion dominates what has been described as Spain's "place in the history of infamy" because of multiple clues about who could have blown up the Madrid trains that killed about 200 people.

Spanish authorities were already on high alert for a possible attack by the Basque terrorist group ETA (Basque Homeland and Liberty) leading to today's national elections. They were quick to blame the attack on ETA. And a new, younger wing of ETA has surfaced.

In the worst terrorist attack to strike Europe since the Pan Am Flight 103 bombing over Lockerbie, Scotland, in 1988, 10 remote-controlled satchel-bombs placed aboard trains and on tracks at three stations exploded while three more were discovered and destroyed. That much is clear. Who conducted the attacks is not.

A van was found within hours of the attacks in the Madrid suburb of Alcala de Henares, where at least three of the targeted trains originated. Investigators discovered seven detonator caps and a cassette tape of Quranic verses in Arabic. Suddenly, Spanish authorities were cautioned "not to rule out anything" in their search for the bombers, even though ETA still was the prime suspect. Al-Qaida loomed darkly as a shadow over the world's latest targeted destruction of innocents.

Complicating the confusion were many conflicting indicators.

For example, while the attack featured the known al-Qaida signature of multiple simultaneous attacks, the bombs were detonated remotely by cell phones, not by the kind of suicide bombers for which al-Qaida has become renowned. ETA has used cell phone detonators.

Further, while the attack featured other ETA signatures such as rucksack bombs and potassium chlorate and titadyne - an explosive compound and booster ETA has used in the past - there was no advance warning, an ETA hallmark. And the attacks claimed far more victims than ETA has ever targeted in the past (its deadliest known bombing killed 21 at a Barcelona supermarket in 1987).

The denials issued by ETA's banned political wing, Batasuna, are to be taken with large grains of salt given the scope of recent ETA plots thwarted by Spanish authorities. Authorities arrested two ETA operatives Feb. 29 and seized over 1,000 pounds of explosives intended for an "imminent attack" in Madrid. Spain's Civil Guard arrested two other ETA suspects Dec. 24 for plotting a series of train bombings.

One of their attacks nearly succeeded, but police found and defused a 44-pound bomb they left on a train heading to Madrid from San Sebastian, in the Basque region.

According to several experts, a new, young and radical leadership has been assuming key leadership positions within ETA, wresting control from the group's more conservative old guard. Indeed, Spanish intelligence recently warned that ETA was still intent on carrying out a massive attack before today's elections.

Then there's al-Qaida. Osama bin Laden threatened to attack Spain and other countries cooperating with the United States in the war on terror in an audiotaped message released in October. Spain has been among Europe's most public and vocal partners with the United States in both the war on terror and the Iraq war.

Additionally, several key al-Qaida cells have been disrupted over the past 2 1/2 years, including a Madrid cell headed by Muhammed Galeb Kalaje Zouaydi that funded the Sept. 11, 2001, plotters in Hamburg, Germany, and conducted the pre-operational surveillance of the World Trade Center and other potential targets in 1999.

Another disrupted cell was connected to the now infamous Abu Musab al-Zarqawi and his network of poison plotters in Britain, France, Italy, Germany and Spain. Interestingly, that network is tied to at least two other attacks claimed - like the Madrid attacks - under the name of the Abu Hafs al-Masri Brigades in Istanbul and Baghdad. The group is affiliated with al-Qaida.

But the claim of responsibility purportedly issued by al-Qaida under the name of the Abu Hafs al-Masri Brigades is as questionable as the evidence pointing to ETA. While the group has asserted responsibility for other attacks tied to al-Qaida, it also claimed to have carried out the August power blackout in the Northeast United States.

Whoever carried out these attacks, the implications for security and intelligence officials are clear: Continued and enhanced cooperation in the war on terror is essential. Spain was not attacked because of its role at the forefront of the war on terror, but despite it. It's clear that terrorist networks are still intent on, and capable of, executing devastating attacks. To combat them, the international community must pool its resources and stay the course.

Matthew A. Levitt is a senior fellow in terrorism studies at the Washington Institute for Near East Policy.