TERRORIST ATTACKS: PARIS, MALI, AND MORE

[Midwest Spy]

I just read that England's MI5, has identified up to 23,000 people that they consider a terrorist threat.

BTW, in the three terrorist attacks in England over the past several weeks, all of the terrorists were known to MI5.

What does that mean?

MI5 knows who these people are but obviously can't do a thing to stop them.