A Homegrown Threat

He was British-born, the son of a Pakistani merchant who had made good in that most British of endeavors: the fish-and-chip business.

But at some point, Shahzad Tanweer, named Tuesday as a suspected suicide bomber in a blast that tore apart an Underground carriage in London last week, became consumed by the rage that has swept across Europe of a new and restive generation of Islamic extremists.

Neighbors described Tanweer, said to be 22 or 23, as a boy who loved sports -- playing soccer in the street or in the park down the road, riding in his car and lifting weights and working out at a local community center. Friends said he had graduated from the University of Leeds with a degree in sports and wasn’t overtly religious.

A young woman who said that she had known Tanweer and his sisters all her life found it hard to reconcile the youth she knew with the man who police believe blew himself up on a crowded train.

Asked whether she thought he might have committed such an act, the woman, who wouldn’t give her name, said, “No, I don’t think, but then again.... No, I don’t think so.”

But as they watched soldiers, police and journalists invade their streets Tuesday, other young neighbors seethed.

They defended Tanweer as a good man who would not have done such a thing. Some, however, came close to justifying violence in response to a perceived assault on Muslims worldwide.

“You see Palestinian kids getting killed on the street in your living room, maybe you’re going to flip,” said a young man who identified himself only as Shakur, 27. It is not a matter of Al Qaeda carrying out attacks, he said. “The people are doing it themselves.”

The attack caught British anti-terrorism officials off guard, but the profile and provenance of the suspects did not.

In recent years, British security services have grown increasingly worried about a unique homegrown threat, anti-terrorism officials say: second- and third-generation youths from the Pakistani immigrant communities that dominate Britain’s Muslim population. Besides keeping tabs on the Arab ideologues and jihadists who for years have made London their headquarters, British intelligence also has stepped up efforts to monitor the cities of Yorkshire and other northern areas where they have seen virulent extremism taking root more quietly but steadily.

“The security services pointed to something that was not imagined before, that there is an indigenous problem,” a British anti-terrorism official said Tuesday. “And that above all it is British-Pakistani. And, almost inevitably, the linkages have been maintained to Pakistan, whether operational or ideological.”

Nonetheless, the suspected bombers slipped past the defenses because they incarnated a variation on a theme recurring from Paris to Milan to Amsterdam: youthful, inexperienced extremists from seemingly well-integrated families who radicalize fast and seem to strike out of nowhere.

“It’s the worst-case scenario,” a British law enforcement official said.

The neighborhoods raided in and around this gritty former textile city in West Yorkshire are not the pretty England of postcards. Although called suburbs, there is little greenery, and some homes are in obvious need of repairs.

Tanweer’s stuccoed, semidetached house on Colwyn Street in the Beeston section of Leeds is a cookie-cutter match to others on the street, slightly peeling and run-down. As police in fluorescent green jackets and tall black bobby hats stood impassively behind the police tape stretched across the street, neighbors edged onto their doorsteps to watch with worried frowns.

The neighborhood of working-class families is a mix of races, religions and nationalities -- with Pakistanis, whites, Africans and Hindus living alongside one another.

“You feel a bit shocked,” said Andy Slater, a driver for an online grocer who lives nearby. “It makes you sick, doesn’t it? It could easily have been Leeds that they attacked. You just get the feeling sometimes that something has to give around here because there is a lot of animosity” between the communities.

The Tanweers, who moved to the Colwyn Street address at least 20 years ago, were considered a success by local standards. Tanweer’s father, Mumtaz, owned the South Leeds Fishery, a neat fish-and-chip shop painted in black and green just up Temple Road, and one or two other businesses. He had bought his house and the one directly behind it for his extended family, raising Shahzad, a younger son and two daughters.

Sabiha, a 22-year-old law student, described the neighborhood as an area of family homes, where everyone knows the others. “We also have a barrister living here,” she said proudly.

She called the Tanweers “a nice family ... very friendly ... really helpful.”

“Everybody is very much concerned about the family.”

Asked about the possibility that Shahzad Tanweer might have embraced an extreme form of Islam, she answered, “What is it that makes you think Islam carries these things? We are Muslims ourselves. They are giving us a bad name.”

Almost all the young Asian men in the neighborhood shun Islamic dress, preferring T-shirts and jeans instead.

Mohammed Ali, 24, working in a community center on an adjoining street, said he had known Tanweer distantly and they had lifted weights in the same gym. Asked how Tanweer and the others might have been persuaded to carry out the attacks, he said, “They must have been brainwashed. They all seem sensible and then they fall into a wrong crowd.”

Asked whether any of the local Islamic preachers were extremists, he said no, but “you may get the odd individual.”

“Whoever did this thing should be punished,” said Ijaz Hussein, a leader at the Kashmir Muslims Welfare Assn., referring to the attacks. “The majority of the community understands what is right.”

But a short distance away, a young man who gave his name as Abdul displayed a hint of the anger against the West and the non-Muslim community that could have been a factor.

Abdul argued strenuously that the Sept. 11 attacks must have been condoned by the U.S. government to provoke anger against Muslims because it could have shot down the hijacked planes if it wanted to. He also repeated the canard that no Jews were in the collapsed World Trade Center buildings and claimed that the U.S. $20 bill had a picture of the attack etched into it.

Many Pakistani immigrant families tend to maintain connections with their homeland, and British-raised generations retain that trait to some extent, the anti-terrorism official said. This has contributed to the “re-Islamization,” as European scholars call it, of young people who seek to remake their identities and, in the process, sometimes find radicalism. The current intensity of global conflicts involving Islam feeds extremism in communities such as Leeds, the official said.

“There’s the issue of Afghanistan, which is right next door to Pakistan,” he said. “There’s Iraq, though that has more influence among Arabs and North Africans. But it all figures. There’s the sense of being under attack as Muslims.”

Yorkshire has seen its share of activity by Islamic extremists. The city of Sheffield was the base for a group of Algerians who planned a foiled bombing in Strasbourg, France, in December 2000, and for a Yemeni-born Briton suspected of participating in a suicide attack in Iraq last year.

As a result, British police announced plans last year to beef up the undercover presence of security forces in the region, although that effort has not been completed, the anti-terrorism official said. Moreover, the nature of Islamic networks has changed as more and more young people become radicalized via contact with the Internet and small, spontaneously formed groups rather than through known mosques or ideologues, making them that much harder to detect.

“It won’t be a shock if they came from nowhere and had absolutely no connections,” the anti-terrorism official said. “But if it was a homegrown group without external support, that would be new. If there were no external resources and they put it all together, that would be new.”

In two previous cases involving Britons of Pakistani descent, Pakistan-based suspects played significant roles, the British anti-terrorism official said. One case centered on a group of suspects convicted recently of stockpiling half a ton of explosive material in a London storage locker for a planned attack on a shopping center or other public places.

The suspects were all between 18 and 22 and had grown up in central and northern Britain as well as London, officials said. They were fervent fundamentalists who worked with an operative in his 30s who shuttled to and from Pakistan providing technical expertise and communications with Islamic networks there, investigators said.

“They were waiting for someone to put it all together,” the anti-terrorism official said. “That plot was not self-contained at all. They needed external technical advice from Pakistan.”

The question of outside leaders or mentors remains crucial in the London bombings because the suspects apparently took the drastic step of committing suicide attacks. Their decision to carry out such attacks against defenseless mass transit passengers, rather than a symbolic “hard target,” such as an embassy or a military base, befuddles many experts. It may be a sign of inexperience or, conversely, a calculated statement by a mastermind who wanted to maximize the psychological impact of the first such attack in the heart of Western Europe.

Suicide bombers almost always require mentors and bomb-makers, so the hunt must focus on such figures, said veteran Italian anti-terrorism official Stefano Dambruoso.

“That’s the most interesting part,” Dambruoso said, “finding out who molded them.”

Daniszewski reported from Leeds and Rotella from London.