Ok, here it goes. This may be waaaay off base, but..... What if the cryptic letter was not for S. but for the police?
https://nypost.com/2020/12/27/nashville-rv-bomber-wrote-cryptic-detailing-holiday-plans-report/
“The attic has plywood and lighting, take a look,” the letter concluded, according to the outlet. “The basement is not normal, take a look. Woof woof Julio”.
So he is an IT guy as I am. One thing for sure, most Communications Hubs have their power and/or back up power in the Basement. Normally if there is a loss of commercial power, the back ups kick in. At least for a limited time, depending on the overall load. So were the outages caused by the explosion due to loss of commercial power? If so, were the back up also down?
Questions? Is it possible he had access to the Building? Had he ever had access to the building or similar Hubs? Did he leave something in the Basement of the AT&T building? Or on the Roof?
He surely would have know that LE would find out about every detail in his life, to include the Houses and the letter he sent S. He is a clever guy. Maybe this is part of his plan. Follow the clues to find the motive.
That letter has some significance. If its fact that neither of the houses have Basements. Then LE needs to search the AT&T building.
JMO, could be waaaay of.