Behind the respectable front of a British government-funded community centre, the two youngest London suicide bombers are believed to have been radicalised by mentors whom they saw as father figures.
Police and the bomb squad yesterday evacuated 200 houses in eight streets surrounding the Hamara youth access point in Beeston, Leeds, to carry out a controlled explosion in the building.
On the surface the project, an offshoot of the main Hamara community building, was doing outreach work with young men and women in the deprived area. But an official working elsewhere in the community, who did not want to be named, said he had reported the goings on at the youth centre to police after he became suspicious that it was a front for radicalising young men.
Shehzad Tanweer (22), the Aldgate (subway train) bomber, and Hasib Hussain (18), the bus bomber, both regularly attended the centre in Lodge Lane, where the Edgware Road (subway train) bomber Mohammad Sidique Khan (30) did youth work. Tanweer and Hussain looked up to Khan as a "father figure", according to one friend, and regularly played football with him as part of the youth project.
A friend of Khan told the BBC he had travelled regularly to Pakistan and Afghanistan to attend military training camps. "He used it [the centre] as a recruitment centre."
Khan and his associates were known for making comments that were "a little strange, extreme", said the man, adding: "I know they were quite upset with what was happening to Muslims around the world, especially with American policy."
A fourth man, Naveed Fiaz (29), who is being questioned by police in London after his house was raided with five others last Tuesday, also used the centre as a base for his youth work.
"We talked to police yesterday because we have got so much information in terms of people who met together in large groups there," said a source.
"There were meetings, meetings, meetings - there didn't seem to be much youth work going on. People came in from outside the community to these meetings. There were people going in there who had nothing to do with youth work. I'd like to think these [the suicide bombers] were three or four guys who misinterpreted the Koran and got in touch with someone from another country - but I don't think that. It goes deeper."
The Hamara centre, which translates as "ours", is within a few hundred yards of the Beeston home of Tanweer, the former home of Khan and a half mile from Hussain's house.
It is an outbuilding of a larger community centre part-funded by the British government's New Opportunities Fund and opened by overseas development secretary Hilary Benn and his father Tony in 2003.
Other young Muslim men distanced themselves yesterday from what was going on in the youth access point. Nasir, a 22-year-old student at the nearby Bradford University, who was one of Tanweer's best friends, said Khan had a huge influence on many young men in the area.
"He was a father figure to lots of young kids round here, they looked up to him. He was a youth worker who used that centre and he used to play football with the young kids. Personally I didn't respect him as a father figure, but lots of kids did. It looks to me like Sidique was the older figure who was influencing them [Shehzad and Hasib].
"I never knew that Sidique and Shehzad and Hasib knew each other well. But I have heard since they had been quite close through this centre and I was really shocked, to be honest."