Initial tests on a letter addressed to President Trump suggested traces of the deadly poison known as ricin. Ricin is found naturally in castor beans. However, it takes considered efforts to turn it into a biological weapon. According to CDC, Ricin can lead to death within 36 to 72 hours from exposure to an amount as little as a pinhead. The letter was intercepted before it reached the White House. The Trump administration hasn’t commented on the reports yet.