Looks like you are likely correct. I just heard on the news that the authorities are now reconsidering what happened and they now furthered the same theory you did.
I used to manage a large courthouse and I can't imagine how this could have happened? I guess the Fulton County Courthouse doesn't have the architectural safeguards we had, and apparently they didn't have the procedural ones either.
I know we hear about the "bad" judges, but I have a lot of respect for them and you seldom hear about the ones that are as down to earth and level headed as anyone you'll ever meet. I cringe when all judges are lumped together as being arrogant or left wing.
I'll tell you one thing, you certainly look at security differently after managing a courthouse. I'm glad I'm not managing one now, given this and the hit on the federal judge's family. Everyone will be on pins and needles for months.