That’s the point, they may say they are convinced, but that doesn’t mean they are.
Why put a suspect on notice you know about them? There’s investigative value to not letting them know, and depending on the situation, there could be value in making sure they know. It can go either way.
At this point we, the public, cannot make that call.
Okay, that's fine, but it's been over two weeks now with probably 1000 cops, the FBI and law enforcement investigators digging into this. And the feds have nearly unlimited resources. Remember, as of now, there has only been one suspect named. Not complex, as if 8 or 12 were named.
And to make things easy, they have the dead suspect, video, the crime scene, his financial data, his profile, witnesses, they interviewed his family, his girl friend, teachers, his neighbors, co-workers and everyone else who knew him.
At this point with all their resources, I'd guess either they have a conspiracy with others involved, or they don't. And I would expect them to advise those in Las Vegas area if they still believe there is still a potential threat...Or not.