The White House has confirmed that a letter addressed to President Barack Obama has tested positive for the poison ricin, reports the Chicago Tribune.
The suspicious letter to Obama contained "a granular substance that preliminarily tested positive for ricin," an FBI statement said. It added: "There is no indication of a connection to the attack in Boston," where three people were killed in bombings at the city's marathon on Monday.
The Secret Service said the letter to Obama was received on Tuesday at a mail screening facility not located near the White House. "The Secret Service is working closely with the U.S. Capitol Police and the FBI in this investigation," Secret Service spokesman Edwin Donovan said in a statement.
The FBI said filters at a second government mail screening facility had "preliminarily tested positive for ricin this morning" and mail from that facility was also being tested.
Thericin-tainted letter apparently came from "from the same sender who mailed a [similar] letter" addressed to Mississippi Republican Sen. Roger Wicker, adds NBC News.
What is happening? Thankfully, no one was harmed in these incidents. #SMDH