Yes, I had heard about this dreadful incident. Must have been on the TV or radio because I don't read papers much.
I think the reason people get so annoyed (no excuse for rioting and violence though) is that this girl and her family would appear to have been in the UK for generations (willing to be corrected) so we have no choice as to whether she lives here or not. The man in Northern Ireland had been granted asylum. A safe place to live from whatever he was fleeing from in his home country, and he repays the favour by trying to murder someone. Unfortunately it has happened too many times with rapes, attacks, general criminal activity being carried out by people we have given a safe haven to and people are sick of it. Yes, I know not all immigrants/asylum seekers are criminals. Yes, I know people who have lived here for generations can also be criminals. We just don't need to be importing more.
The whole system needs a thorough overhaul so that we can be sure who we are letting make their lives here. We don't go out without locking our doors because we don't want just anybody to make free with our homes. It should be the same with our country.