(WASHINGTON) -- A suspicious letter, potentially laced with the poison ricin, was sent to the office of Sen. Roger Wicker of Mississippi, ABC News has learned.
Senate Majority Leader Harry Reid confirmed to ABC News that Capitol offices were on high alert. He referred questions to Capitol Police.
Two sources confirmed the letter was sent to Wicker, R-Miss., but did not arrive at his office on Capitol Hill. It was stopped at a mail processing facility.
According to Terrence Gainer, the Senate Sgt. at Arms, the letter was postmarked in Memphis, Tenn.
Wicker's Dirksen Capitol Hill office is closed for the evening, as it is after office hours.
Aides in Wicker's office emphasized that at no point did the senator's office evacuate or close because of the threat.
"Once we get information from Capitol Hill police, we will send out more," an aide to Wicker said Tuesday evening.
Wicker came to the Senate in 2007 after more than a decade in the House. He was appointed by then-Gov. Haley Barbour of Mississippi.
The reports of a poisonous letter rekindled memories from 2004, when ricin was found in the office mailroom of Senate Majority Leader Bill Frist, Republican of Tennessee. In the weeks after the terrorist attacks of Sept. 11, 2001, letters containing anthrax were sent to Capitol Hill, which prompted major changes in security and screening protocol of all mail.
Senators were made aware of the letter sent to Wicker on Tuesday night during a closed-door briefing about the Boston attacks. The Senate Sergeant at Arms, Terrance Gainer, warned senators about the letter and outlined a series of precautionary steps to be taken, including the suspension of mail to the Senate.
A senior Senate official told ABC News that authorities had identified and were interviewing a person of interest – someone who frequently writes letters to members of Congress. There were no injuries, but the senior official said the event was being treated as “totally real.”
Members of Congress were also taking extra security steps at their district offices in their home states.
“It rarely gets to the member before it goes through a lot of staff,” said Flake, the Arizona senator. “That’s a big concern obviously for all of us. So we are very anxious to get more details on this.”
Homeland Security Secretary Janet Napolitano, on Capitol Hill, declined to comment Tuesday night on the suspicious letter.
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