Update: A letter sent to President Barack Obama that was intercepted at an off-site facility tested positive for ricin, according to the FBI.
The envelope, which was addressed to the White House, was immediately quarantined.
Original Metro story below:
Parts of the U.S. Capitol were cleared after suspicious packages were found on the first and third floors of the Hart Senate Office building, according to a report by CNN.
Suspicious envelopes were also found in the Russell Senate Office Building and at the office of Sen. Richard Shelby of Alabama.
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According to the report, a man with a backpack is being questioned after he raised suspicion with the content of his bag and the way he responded to police questions.
One of the officers said the man’s backpack contained more sealed envelopes.
According to a report by Reuters, a “suspicious substance” has been found inside a letter addressed to President Barack Obama at the White House.
A similar letter was sent Tuesday to Mississippi Sen. Roger Wicker. Preliminary tests show the envelope contained the deadly poison ricin.
The letter was sent to a lab for further tests.
There is no connection between these letter and the attacks at the Boston Marathon on Monday.
"The investigation into these letters remains ongoing, and more letters may still be received. There is no indication of a connection to the attack in Boston," the FBI said in a statement.