Mmm.. This guy had criminal history and was active online.
Dylan Roof (A month ago.. Shooting in the church) had a website.
Also, a terrorist has a lot more financial backing, obsesses over hurting people and is far more organised. Still the system manages to keep us safe from them, because laws help them to do so. Joe Shmo has fewer resources at his disposal. The only advantage is that he lives in our neighborhood.. And we allow him to walk to a shop and buy guns.