The only reason I know what the poison ricin is, is because I've seen every episode of Breaking Bad at least twice, Walt & Jessie used ricin to "off" a few people.  It appears somebody else, only in reality, thinks ricin is a great way to kill someone, namely, the president of the USA, Barack Obama!  He received a letter in the mail that contained the deadly toxin inside of it confirms the FBI.

Ricin comes from the castor oil plant, Ricinus communis, and a dose about the size of a few grains of salt is enough to kill an adult human if inhaled, ingested or injected.

This comes just after a letter sent to Senator Roger Wicker was found containing the same poison in it!

NBC is reporting that the letter to the president also contained ricin and was sent by the same person. The substance in the letter to the president has thus far only been described as "suspicious" by Secret Service spokesman Brian Leary.

Both of the letters arrived on Tuesday (yesterday, April 16th), at different post offices. The letter to Senator Wicker came from Memphis, Tennessee, but had no return address. At this time, the Secret Service, the FBI and the Capitol Police are all investigating.

As more details come in, I'll be updating with them.

I can tell you this, even though ricin is lethal if inhaled, ingested or injected, even so much as touching it can cause rashes and sickness, though it's not fatal if it was merely touched.