Profile: Hasib Hussain
Teenager Hasib Hussain was known as a quiet student with few friends whose life attracted little outside attention during his early teens.
Hussain, like two of the other bombers, Mohammad Sidique Khan and Shehzad Tanweer, was a second-generation British citizen whose parents were of Pakistani origin.
He grew up in Holbeck, on the outskirts of Leeds. The youngest of four children, he was still living with his parents when he died.
He was not a high achiever academically, and although he liked sports, he was never outstanding.
He was involved in a brief period of racial tension at the school, but was not a known troublemaker.
Hussain left school in July 2003 with seven GCSEs and went on to study business, a course he finished a month before the bombings.
One neighbour described the family as "very nice people".
"We all knew them but I wouldn't say I knew them well. They were just a very nice family," he said.
'Al Qaeda - No limits'
A year before leaving school, Hussain went to Mecca to do the Hajj pilgrimage and went to Pakistan to visit relatives.
On his return to the UK, he was noticeably more religiously observant - he grew a beard and began to wear traditional robes - something he later stopped doing as he began working on the bomb plans.
Not long after his return from the pilgrimage, someone noticed he had written 'Al Qaeda - No Limits' on his religious education school book.
He would speak openly of his support for the radical movement and said he believed the 11 September bombers were "martyrs".
He also told teachers he wanted to become a cleric when he left school.
Much of his social life was based around the local mosques, youth clubs and the gym in the neighbouring district of Beeston, where fellow bombers Khan and Tanweer grew up. Hussain was part of their inner circle, attending the same events and gatherings, sharing their most intimate plans and thoughts.
What appears to have happened is that by 2004, he was signed up to Khan's jihadist cause - although it was not clear during that year what Khan specifically wanted to do.
When MI5 were watching another plotter who met Khan in the early part of that year, the Leeds man appeared to be talking about going abroad to fight. In the bugged conversation, Khan refers to "another brother we've got who's just coming in…" He suggests that this unnamed 18-year-old becomes a contact point for others if he himself goes to fight overseas.
In the months before the attacks, Hussain had rented a small flat in the Chapeltown area of Leeds that was to be the first property used as part of the plot.
When the landlord tried to visit to warn his new tenant about a possible electrical fault, Hussain blocked the keyhole and warned him he could not enter because he was possessed.
'Just visiting friends'
Hussain explained away his trip to London by telling his family he was going to visit friends.
But when he failed to return, his parents reported him as missing to police, fearing for his safety in the emerging reports of the bombings.
He had in fact boarded the No 30 bus in London armed with enough explosives to rip it apart and to kill 13 people. His driving licence and cash cards were found in the wreckage.
In a statement, his family later said Hussain had been "a loving and normal young man who gave us no concern".
"We are having difficulty taking this in," they said.
"Our thoughts are with all the bereaved families and we have to live ourselves with the loss of our son in these difficult circumstances.
"We had no knowledge of his activities and, had we done, we would have done everything in our power to stop him."