If it was black hat, they would have set it off during high traffic mid day and set up a free beer display to bring in more bodies. Within 10 min they would have an 'evil trump supporter' to blame with a full backstory. They would never give a warning and enough time to get EVERYONE clear.
Someone needed this building / center gone. What changes now that it is gone? One thought is does it have an impact on the presidential alert system? would you be able to stop a presidential alert from here or remotely if this building was intact?