The British are very good detectives, but that isn't stopping the investigation in London from taking unexpected twists and turns. The story already has been revised in three important ways since the bombings last Thursday. Today, evidence emerged that at least one and perhaps all four of the bombers, whom police say they have identified, may have died in the attack. That contradicts the initial assumption that the London bombers, like the ones in Madrid last year, planted the bombs and fled. If true, it would make London the first European city to have suffered a suicide bombing. The British also have concluded that the bombs used were industrial or military-grade explosives rather than crude devices, as was initially believed. And investigators now think that the three bombs on the subway were coordinated and went off within 45 seconds of each other. (The bomb on the double-decker bus blew up nearly an hour later.)
These revisions should be taken in stride, because investigations of this kind of terrorist attack are rarely smooth and linear. British and American investigators of the December 1988 downing of Pan Am 103—the deadliest terrorist attack in United Kingdom history, with 259 killed on board the plane and 11 on the ground in Lockerbie, Scotland—ran through three theories for the crash before hitting on the right one. Initially, London and Washington believed that Syria had hired a Palestinian hit squad; next they thought Iran should be held responsible. Then, more than a year after the attack, a massive sweep of the Scottish countryside paid off. Police moving slowly, shoulder-to-shoulder, discovered unimpeachable forensic evidence: a sliver of a circuit board from the bomb's timing device the size of a thumbnail. A match between the circuit-board fragment and a Libyan-built timing device photographed in Africa revealed Tripoli's role.
The key to that investigation may prove useful this time as well. It is unlikely that the four men who investigators think planted the bombs were the ones who built them. As British Home Secretary Charles Clarke put it today, the detonators were the "foot soldiers" of a larger plot. Behind them was a bomb maker who investigators believe assembled all four devices. Sophisticated bombers are a finite resource: That's why the Israelis make a point of going after them. They're also idiosyncratic, and even the most skilled leave behind a signature. The CIA has a bomb archive that includes photographs, descriptions of countless devices, and pieces of debris from previous bomb sites. These can be used to identify the fingerprints of most bombers who have pulled off a previous attack. In the days and weeks to come, the British will painstakingly comb the crime scene for remnants of the four bombs detonated in London in an attempt to identify their maker. They will hope that this is not the bomber's first attack and that he traveled to London to do this work—he most likely is not native to the United Kingdom. Both scenarios would make it easier to find more clues by making it possible to identify him through evidence of his work elsewhere or possibly at other sites through analysis of immigration records. If he didn't use his name to enter the United Kingdom, he may have slipped up by using a known alias.
Almost immediately after the London attacks, investigators began scanning the faces caught on security cameras in the Tube on Thursday. This will be slow work: An estimated 3 million people pass through the London subway system each day. The British will also look at the security tapes from the days before the attack—if tapes are kept that long—because terrorist incidents are preceded by intelligence collection. The Sept. 11 hijackers rode transcontinental flights weeks before they flew into the World Trade Center and the Pentagon in order to determine when cockpit doors were open and the movements of the flight crew after takeoff. One advantage that American investigators had was that the 19 hijackers used their own names to buy airline tickets. It is perhaps too much to ask that the London bombers bought monthlong subway passes, which require a photograph.
Other forms of intelligence may also help solve the crime—especially if the terrorists failed to cover their tracks, as others like them have in the past. Mohamed Rashed Daoud al-Owhali, one of the intended suicide bombers in the August 1998 attacks on the U.S. embassies in Kenya and Tanzania, lost his nerve and jumped from the cab of the Nairobi truck-bomb before it blew up. He then called a Compact-M satellite telephone linked to Bin Laden to ask for assistance. According to the records from the U.S. trial of the East African bombers that followed, that phone had been purchased in the United States using a British credit card, and Bin Laden had used it at least 200 times over two years to call from Afghanistan to his chief lieutenant in London, Khalid al-Fawaz. British intelligence had been monitoring these calls, and agents were listening the day al-Owhali dialed Bin Laden's number. Meanwhile, fax machines linked to al-Qaida by the British and the United States began to issue statements claiming credit for the East African blasts. Together, the links gave the CIA solid proof that Bin Laden had ordered the attack on the embassies—proof that led Bill Clinton to retaliate with the cruise missile attack on al-Qaida camps in Afghanistan.
Yesterday's raid of six homes in the West Yorkshire town of Leeds shows that the British are already making progress. A missing person's report from a Muslim family, along with personal effects found at three of the four bombing sites, led to the identification of the four suspected bombers, who reportedly boarded subway cars together Thursday morning and may have died near the seats where the bombs were placed. The British have arrested one suspect who is alleged to be a relative of one of the suspected bombers. If the attack turns out to have been a coordinated suicide bombing, the British will continue using these leads to track down others in the bombers' supporting network. As Israeli investigators discovered long ago, suicide bombers are not self-contained operators. They need logistical support and cover while they prepare an attack.
There is one troubling aspect so far of the British investigation: With an Islamic population of 2 million that has a history of radicalism, the British doubtless had in place a system of Muslim informants, especially in poor areas like West Yorkshire, with sizable unemployed Muslim populations. Yet either the informants missed the planning for the attacks, or British intelligence overlooked the chatter they reported. That lapse is a reminder that even in a time of heightened security, important warnings can be missed.
Although the breakthroughs in the United Kingdom today and yesterday are encouraging, it is worth remembering that not all terrorism cases get fully solved. In December 1975, a bomb ripped through a baggage claim area at LaGuardia Airport used by TWA and Delta, killing 12 people and injuring an additional 74. Nearly 30 years later, the FBI is still not sure who planted it. Many important unknowns remain about the Madrid attack last year, the most important being whether there was a mastermind behind the local group of Moroccan immigrants who staged the bombings.
The challenge now for the British is to determine whether they are hunting a large organization, with direct ties abroad, or a local jihadist gang. There is much debate now about the extent to which al-Qaida has metastasized in reaction to U.S. and allied attacks on Bin Laden's sanctuary in Afghanistan. There is no question that the group has devolved into a looser worldwide confederation. The question is whether it has also become more lethal. The solution to the London case may provide some answers. Counterintuitive as this may seem, it would be comforting to learn that these four suspected bombers relied on outside help. That would indicate that they are part of an army of terrorists, and armies have leadership structures that can be destroyed. If, on the other hand, the London bombings were done by four angry young men with the barest amount of local support, the challenge for Western counterterrorism becomes much greater.