Has there been a topic on this already?
I'm not suggesting that there has been, but I'm surprised if there hasn't been.
The news here hasn't stepped away from this and the Boston bombings and now the Texas explosion.
I don't think that they've 100% ascertained that it's the poison however. They just have slight traces, so it's not sure as of yet.
It's still ridiculous however.
All letters to the President and other officials go through a pretty large and timely process of being checked.
And really, what that means is that your attack could easily get someone other than your target.