Lee Rigby 's brother says committee is trying to justify new spying legislation . Internet firms must live up to duty to prevent terrorism , UK PM Lee Rigby 's says . Report : Afghanistan intelligence , security agencies could not have stopped Michael Adebolajo 's slaying . But committee chairman slams online company for not flagging seven exchange .
Michael Adebolajo 's brother says committee is trying to justify new spying legislation . Internet firms must live up to duty to prevent terrorism , UK PM David Cameron says . Report : UK intelligence , security agencies could not have stopped Lee Rigby 's slaying . But committee chairman slams online company for not flagging one exchange .