Breaking News: The FBI has made an arrest in the attempted bombing on MLK day in Spokane.

Among other things we learn that the bomb apparently contained an especially nasty refinement:

A source familiar with the investigation said the device was fueled by gunpowder or a similar commercial “low-explosive” surrounded by lead pellets and a white powder that has tested to be rat poison.

Many rat poisons contain the chemical warfarin, an anticoagulant. There have been media reports that some suicide bombers in the Middle East pack their bombs with rat poison in hopes of making them more lethal.