Concern Rises Over Blasts Probe

European anti-terrorism officials helping British counterparts investigate last week’s bombings here expressed increasing concern Monday about the apparent lack of progress in the case and the potential for new attacks here or on the Continent.

British officials urged patience, saying they were focused on painstaking forensic work. The hunt for clues has been slowed by difficult access to subway tunnels and the size of the scene of a bus blast, where police have to scour trees and grass in a nearby park for human remains, British and European investigators said. As the work continued, the number of confirmed deaths rose to 52, and the first victim was identified.

A British law enforcement official acknowledged that the nation’s spy services were caught off guard by the plotters’ ability to avoid generating the warning signs that often precede attacks, even vague intelligence indicators, known as “chatter,” that can be understood only in retrospect.

“They had no idea it was coming,” said the British law enforcement official, who asked not to be identified. “There was no background noise, no last-minute intelligence.”

Speaking in Parliament on Monday, Prime Minister Tony Blair said: “I know of no intelligence specific enough to have allowed them to prevent last Thursday’s attacks. By their very nature, people callous enough to kill completely innocent civilians in this way are hard to stop.”

There are increasing fears among European anti-terrorism chiefs that the bombers were as adept at covering their tracks as they were at concealing their preparations.

“The British seem to have very little,” said a senior European police official who hurried to London this weekend to work with British counterparts. “I think part of the problem is that too many Islamic groups developed in Britain. You can monitor two or three, OK, but when you have 10, the situation becomes toxic. They were overwhelmed.”

The official and other colleagues from the mainland said they respect the professionalism of British investigators, who invited experts from an array of Western security services to a weekend briefing.

Nonetheless, European officials said the British provided little more information than they have in news briefings. The British have shared little evidence and have made few requests for help tracking potential suspects or pursuing leads, European and U.S. anti-terrorism officials said. That’s unusual in Europe, where Islamic networks inevitably sprawl across often unguarded borders and where close international cooperation has become routine and vital.

Because British law enforcement has a meticulous and discreet style, it could be that the silence masks progress as authorities conduct delicate surveillance or nail down leads.

“Either they have nothing, or they have something good and have decided to keep it quiet for the moment,” a senior Italian police official said. “I hope for the sake of all of us that they have something good.”

Nonetheless, concern intensifies because the lack of arrests combines with the urgent menace of new attacks. Four recent attacks by Islamic terrorists were planned as opening salvos in violent offensives.

In Istanbul, Turkey, in 2003, bombings of synagogues were followed five days later with bombings of a British consulate and bank. Police in three interconnected cases -- the Casablanca, Morocco, bombings in 2003 and attacks in Madrid and Amsterdam last year -- foiled planned follow-up strikes.

Because the British have told their neighbors that they have not zeroed in on any particular network, police elsewhere find it hard to focus their response, the European anti-terrorism chiefs said.

Spy services have stepped up surveillance of Moroccan-dominated networks they see as prime suspects in the London bombings because they are “the most active and ferocious at the moment,” in the words of an Italian law enforcement official.

Moroccan extremists allegedly had lead roles in the Madrid train bombings.

British domestic intelligence services are skilled at infiltrating networks and tend to let extremists operate in order to collect intelligence, confident that they can abort attempts at violence, anti-terrorism officials say. That’s why some experts are surprised that there have not been arrests.

“I find it curious that there have not been advances,” a French intelligence official said. “Usually, you have leads through intercepts, through informants separate from the direct investigation.”

Fairly or unfairly, the aftermath in London has been compared with that of the Madrid train bombings, which were similar in methods and targets. Spanish police arrested key suspects in that case just two days after the blasts.

The Spanish police already had been monitoring many extremists through surveillance and informants, including a double-agent imam. The prior intelligence work was the context for a lucky break: an unexploded bomb that helped lead to a key suspect.

In addition, Spanish police quickly shared detailed technical evidence and intelligence with European counterparts, according to investigators who went to Spain to assist them.

The forensic work in London slogged forward Monday. Metropolitan Police Commissioner Ian Blair, no relation to the prime minister, said police had collected 2,500 tapes from security cameras and were sifting through about 2,000 calls from the public to an anti-terrorism hotline.

The police commissioner spoke to reporters outside King’s Cross Station after inspecting the narrow, deep and hot Tube tunnel there, where recovery workers were still trying to extricate human remains from beneath the bombed-out carriage of a Piccadilly line train.

“Every square centimeter of it, and that’s hundreds of yards of tunnel, a whole train -- and then that is only one of the four scenes -- has to be meticulously combed. It is a long, long job,” he said.

The police chief declined to comment on a theory, published in several British papers Monday, that said the bomb planters may have met up at King’s Cross Station to launch the attack. All three trains that were bombed had been through the station.

Police also stayed silent about the lingering mystery of the bus explosion. The suspicion remains acute that a terrorist died aboard the bus as the result of an inadvertent or premature explosion, British and European police say. But DNA testing could be required to reach solid conclusions.

The bus case remains ambiguous, a U.S. official said Monday, declining to reveal whether police have even determined the ethnicity of the bomber. Overall, the investigation is “still in the opening innings,” and investigators are pursuing more theories than solid leads, the U.S. official said.

The theories center on a new generation of European Islamic extremists who are harder to identify because they radicalize quickly and spontaneously, relying on the Internet as much as mosques or known ideologues, experts say. There is even a theory that the culprits were converts from non-Arab backgrounds, according to a U.S. law enforcement official.

Some top European investigators subscribe to the theory that jihadis returning from the war in Iraq either carried out the London bombings or provided leadership and explosives expertise to a local cell.

That fits with recent intelligence reports that battle-hardened operatives were redeploying from Iraq to Europe intent on bringing jihad to the West at the behest of Abu Musab Zarqawi, Al Qaeda’s leader in Iraq, European police officials said.

“There was an intelligence report two months ago from the Americans that Zarqawi had sent a hit team of 20 people to Europe with the intention of committing attacks in various places, among them London,” the Italian police official said. “But it was not confirmed.”

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Times staff writer Greg Miller in Washington contributed to this report.