Some 12 hours before he blew himself up on the London underground, Shehzad Tanweer was playing cricket until late evening in a park in northern England.
"He appeared perfectly normal to those around him," said a government report on the London attacks of July 2005, in which four young, apparently unremarkable British Muslim men killed 52 people in Western Europe's first suicide bombings.
Tanweer's last cricket game is one small detail that hints at the enormity of the challenge facing European security services one year later: how to spot the "homegrown" militant who betrays no outward sign of hostile or erratic behaviour.
"It's like looking for a needle in a haystack," said Peter Waldmann of the University of Augsburg in Germany, one of a panel of terrorism experts whom the European Union has consulted on the issue of Islamist radicalization and recruitment.
As the British Government report made clear, there is no single type of militant personality. Some recruits have been poor, but some affluent; some ill-educated but others from prestigious schools; some with criminal records but others "clean;" some single but others with partners and children.
"All the cliches that we have about the poor, the radical upbringing at home, they're just blown out of the window. There is no ultimate type of characteristic, there is no cliched person who would become a terrorist," said Sebestyen Gorka, professor of terrorism studies at the George C. Marshall Centre in Germany.
According to Gorka, it makes more sense for security services to focus on certain types of group behaviour than to look for individual characteristics of potential terrorists.
"Usually you see people who are friends together, who are colleagues together or who are related, people who know each other first before they become extremists and who join the terrorist organizations as a group," he said.
"If you find a group of people together who really do hang out together, who eat together, who go to the same cleric for example, that is a unit that is easier to pick up in terms of surveillance ... It's easier to pick up a large blip that is suspect than one individual who is suspect."
For Waldmann, a key stage in radicalization is the point at which the militant travels abroad and creates both physical and symbolic distance from home.
"When they suddenly decide to go to Yemen or Pakistan, it's not just important for possible training, like learning to use weapons, it's a symbolic cut-off," he said.
"To carry out a terrorist attack on a country, you have to really hate it, you have to totally reject it. I have the impression that this distancing (through travel) is important ... You suddenly see things through a different lens."
In the case of the London bombings, two of the plotters visited Pakistan between November 2004 and February 2005, and the group maintained contact with one or more individuals there in the run-up to the July 7 attacks.
The extent of possible al-Qaida direction from Pakistan is one of many unknowns that investigators have yet to determine.
Three of the four bombers had Pakistani immigrant backgrounds. That has prompted other countries to reassess the threat from angry, disenchanted sons and grandsons of Muslims who may have lived in Europe for decades but in many cases have never fully integrated into Western societies.
"Until now, people had thought the second generation was not that susceptible that it was heavily burdened by identity conflicts, discrimination or whatever, but that there was a world of difference between dissatisfaction, protest and terrorism," Waldmann said. "Now it's the second generation that's in the sights of the investigators."
Source: China Daily