AP source: Envelope addressed to White House contained ricin

Federal officials intercepted an envelope addressed to the White House that contained the poison ricin, a U.S. law enforcement official told The Associated Press on Saturday. The letter was intercepted at a government facility that screens mail addressed to the White House and President Donald Trump, the U.S. official said. A preliminary investigation indicated it tested positive for ricin, a poison found naturally in castor beans, the U.S. official said.