Where did the hatred that led to the murder of a soldier in Woolwich come from? Radical hate preacher Anjem Choudary knew one of the assailants and says he is proud of having “a big influence” on his life. The attack demonstrates how difficult it is to prevent Islamist violence in Britain.

Anjem Choudary grabs a can of Red Bull before he talks about the man with the blood-soaked hands and a meat cleaver — a man who is an acquaintance of his. Choudary doesn’t call what happened in London last week murder, but rather “the operation on Wednesday.”

Wearing a dark robe and sporting a beard that grows down to his chest, Choudary sits down at a table in a café in the northeastern part of the city. The press generally portrays him as a hate monger. In the mid-1990s, he founded the now-banned Islamist organization al-Muhajiroun, in which Michael Adebolajo later participated on a regular basis — the same man with the meat cleaver who hacked a British soldier to death so savagely, and so publicly, that an entire country seemed briefly in shock.

Choudary and Adebolajo know each other well. Between 2005 and 2011, Adebolajo often attended demonstrations organized by Choudary. Usually they protested the wars in Afghanistan and Iraq, the “crusade of the infidels” against the Muslims, as they called it. In video footage shot by the BBC in 2007, Choudary and Adebolajo can be seen together at a protest in front of a London police station. Choudary is barking into a megaphone. Adebolajo is clad in a white robe and has a serious expression on his face.

Over a period of five years, the two men regularly met, and Adebolajo occasionally listened to Choudary’s sermons. He was “a pleasant, quiet guy” when he first met him, says Choudary, who adds that he was surprised to see him again on TV last Wednesday.

On the televised images, the erstwhile pleasant and quiet Michael Adebolajo, 28 — together with his friend Michael Adebowale, 22 — is standing on a street in the South East London neighborhood of Woolwich on a dreary Wednesday afternoon and wielding a meat cleaver and a kitchen knife. His hands are covered in blood. Passersby are standing nearby and filming him with their mobile phones. On the street behind him lies the lifeless body of soldier Lee Rigby, 25, an infantryman and drummer who performed ceremonial guard duties at Buckingham Palace. “The only reason we have done this is because Muslims are dying every day,” Adebolajo shouts into the camera, adding: “The British soldier is an eye for an eye, a tooth for a tooth…”