A mother confronted the Woolwich attackers, asking them to hand over their weapons and warning them: "It is only you versus many people, you are going to lose", it was reported.
Ingrid Loyau-Kennett, 48, told the Daily Telegraph that one of the attackers said to her that they "want to start a war in London tonight".
"So I thought 'OK, I don't know what is going on here' and he was covered with blood. I thought I had better start talking to him before he starts attacking somebody else. I thought these people usually have a message so I said, 'what do you want?'"
Mrs Loyau-Kennett said that the attacker seemed to be "in full control of his decisions and ready to do everything he wanted to do."
The mother-of-two, a cub scout leader from Cornwall according to the report, added: "Being a cub leader I have my first aid so when I saw this guy on the floor I thought it was an accident - then I saw the guy was dead and I could not feel any pulse."
ITV News has uncovered a video showing Woolwich suspect Michael Adebolajo speaking at a demonstration at Harrow Central Mosque in 2009.
Documents suggest Security Services were trying to recruit Woolwich suspect Michael Adebolajo and had also approached members of his family.
Police in Kenya say they did everything they could to highlight their concerns about Michael Adebolajo.