with this bomber. He was well known to them, he'd been to Libya and Syria, had known links to Al Qaeda and members of his own family had informed on him saying he was dangerous.
It is a very odd society that believes the right of some hairy fvckwit who supports ISIS to walk freely trumps that of women, children and gays to go to an Ariana Grande concert without getting blown apart, isn't it?
Anyway, it's easy to keep them under surveillance. What you do is round them up and put them on a camp on the Isle of Man.