This seems a little out of place in Spokane. There really isn't much of a Black population in Eastern WA. More Islamic population than Black. There are still a few white supremacists, but they keep a real low profile and bombing MLK parade would certainly get the FBI breathin' down their necks. Something they have avoided since the days of Richard Butler.
If I were to chance a guess, my money would be on some stupid little high schooler wantin' to make a name for him/them selves. Or givin' the complete dud the left had over the Ariz shooting, it wouldn't surprise me if it's a false flag. Not many lefties in this neck 'o the woods though, so best to wait for the Feds to run it down.
ETA:
Called one of my buds down at the sheriff's department and it looks like you can rule out some nutjob high schooler! He said the sophistication of the device is such that it has to be someone with a great deal of knowledge in explosives! So much so, that white supremacists are gettin' lower on the list as the intricate device is such that they haven't seen anything like it before! It's closer to the IEDs the military deals with!
They are offering a $20,000 reward for info. They are definitely calling it a domestic terrorist event! Anyone keepin' track of Ayres or Dorn lately?
My buddy said he will keep in touch if they give him any new info.