Michael Adebolajo, London Attacker, Influenced By Al-Shabab, Radical Preachers

London - The slaying of a British soldier in southeast London cast a spotlight on radical preachers that influenced Michael Adebolajo, the attacker seen in videos with bloody hands holding a butcher knife. It also raised questions about the reach of the terrorist group al-Shabab, after a British government official said one of the two men tried to go to Somalia to train or fight with the group. The official spoke on condition of anonymity because he was not authorized to speak about the police investigation.

Here's a look at the preachers and al-Shabab.