Gotta say, this is actually a distinct possibility to bear in mind regarding the bombing in Nashville:

My guess is that since it was in front of the AT&T headquarters building, on a early holiday morning with few people out, it was a disgruntled employee that wanted to cause real property damage but tried to warn the people the bomb go off. Hence the pre warning. Just a guess!

— Nick (@NickM538) December 25, 2020

Could easily be a former employee, maybe someone who got laid off or fired, and now has an axe to grind against AT&T.