Inside al-Tawhid mosque in Leyton, east London, the atmosphere was nervous as volunteers unlocked doors ahead of Friday prayers.
Amid reports that Khalid Masood had worshipped at the mosque in recent years, a member of its management, who declined to give his name, said: "We don't know anything about this person. If he ever attended, from the name we don't know him. The images of him aren't clear enough for us to know if he ever attended the mosque."
The mosque's tiny brick frontage on Leyton High Road leads to several large prayer rooms, with attendance on Fridays sometimes reaching 600. Some of those streaming towards the mosque for lunchtime prayers pointed out that it was impossible to know the identity of all those attending. "People come and go," shrugged a volunteer in the mosque's cramped office.