CNN understands that one line of inquiry being examined in the Woolwich terror investigation is that Adebolajo might have attempted -- but failed -- to travel to Somalia some time last year.
Al-Muhajiroun connections claimed
A self-proclaimed former radical associate of Abu Nusaybah told CNN terrorism analyst Paul Cruickshank he had been a follower of the group Al-Muhajiroun, a British group of Islamic extremists virulently opposed to UK intervention in Iraq and openly supportive of al Qaeda.
The former associate -- who spoke to CNN on condition of not being named -- spent time with Abu Nusaybah in Al-Muhajiroun study groups in Luton, a town north of London, in the years leading up to the July 7, 2005, attacks on London's transit system, he said.
At the time, Adebolajo himself was a follower of the group and attended meetings in London, according to several Al-Muhajiroun insiders, before moving away from the group two or three years ago.
"Abu Nusaybah was very quiet, always smiling, and very religious," said his former friend, who has now shed his radical views.
He said their circle of friends in Luton included Taimour Abdulwahab al Abdaly, who carried out a suicide bombing in Stockholm in December 2010 in which he was the only fatality.
He said Abu Nusaybah had connections to a group of Somali extremists in Luton.
It is understood that the two individuals suspected in the knife and cleaver attack were known to Britain's domestic security service. They had featured in previous investigations into other individuals, but were not themselves under surveillance.