The Senate sergeant-at-arms broke the news to members in a classified briefing, saying that the substance was intercepted at an off-site facility where Congress gets its mail, according to several lawmakers. It was tested repeatedly.
“It was caught in the screening facility. That’s why we have an off-site screening facility for mail,” said Sen. Claire McCaskill (D-Mo.). “The system worked the way it was supposed to.”
She added that authorities may suspect an individual who often wrote to senators. Other senators did not describe a suspect.
“There is an ongoing investigation,” said Sen. Richard Blumenthal (D-Conn.). Senate Majority Leader Harry Reid (D-Nev.) told reporters as he left the briefing with FBI Director Robert Mueller and Secretary of Homeland Security Janet Napolitano that the letter was addressed to Wicker. Mueller and Napolitano also presented detailed information on the Boston bombings.
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