The LaSalle National Bank Building? This doesn't sound like terrorists, it sounds more like when the Rose Law firm in Little Rock had a convient fire.
ping
The EAST side of the building, according to WLS TV is showing the flames from the windows...the west and other sides just have smoke coming out the windows.
No sign of fire fighters in the floor below, the lights are still on in the windows in the floor below...nothing like smoke etc. from burning thru.
More to come...
I posted my reply before I read yours. I'm glad I have company in this matter.