LONDON -- Investigators have linked one of the suspected London suicide bombers to a group of alleged extremists arrested here last year in a foiled terrorist plot by a Pakistan-based Al Qaeda group, authorities said Wednesday.
Mohamed Sidique Khan, a 30-year-old primary school teacher, has emerged as a key figure among the four suspected bombers, European and U.S. investigators said. Although officials had said that Khan and the other three were unknown to security personnel before last week's attack, investigators now think Khan was an associate of some of those arrested in last year's plot.
That strengthens suspicions that the London attacks were carried out by an Al Qaeda branch that teamed Pakistani masterminds with Pakistani British operatives and had tried to strike Britain before, investigators said.
Authorities believe that Khan and the other suspects, who traveled extensively to countries including Pakistan, Afghanistan and Saudi Arabia, received training from Al Qaeda specialists. Khan may have helped recruit and prepare his fellow bombers, who, like him, were Pakistani Britons from the northern city of Leeds, investigators said.