A ricin letter mailed to President Obama was intercepted by the Secret Service on Thursday. The text of that mailing was identical to the letters sent to New York City Mayor Michael Bloomberg and his gun control advocacy group in Washington D.C., which threatened "What's in this letter is nothing compared to what I've got planned for you," police and law enforcement sources said. The letter to Obama was detected by the Secret Service at the White House off-site mail sorting facility.
The letter has tested positive for ricin in lab analyses. Ricin, which is derived from crushing castor beans, causes failure of the respiratory and circulatory systems within 36 to 48 hours of inhalation, injection, or ingestion. It is, however, difficult to produce ricin in its most dangerous gas state. There is no known antidote for the toxin.
In the mayor's case, the letter contained a "pink-orange oily substance." In that form ricin is easy to identify and therefore posses a lesser risk. The two letters recieved by Bloomberg on Wednesday appear to be of the same origin, threatening Bloomberg for his anti-gun efforts. Bloomberg responded to the threat, saying: "The letter obviously, referred to our anti-gun efforts but there's 12,000 people (who) are going to get killed this year with guns and 19,000 that are going to commit suicide with guns, and we're not going to walk away from those efforts."
Obama and Sen. Roger Wicker (R-Miss.) were also sent ricin-tainted letters in April 2013.