Authorities with the Federal Bureau of Investigation said they have positively identified who sent the letters, but no arrest was made because authorities were waiting for further test results for confirmation.
The feds say they do not believe there is a connection between the poison-drenched letters and the terrorist attack during the Boston Marathon. Filters at a second government mail screening facility also tested positive for ricin in preliminary screening Wednesday.
As a precaution, authorities cleared the atrium of a Senate office building Wednesday and were investigating a suspicious package there. Capitol police were also investigating a suspicious package at the office of Sen. Richard Shelby, R-Ala. Shelby’s staff had not been evacuated.
The FBI confirmed the preliminary positive test on the Wicker letter Tuesday. That letter was intercepted at a postal facility in Maryland that screens mail sent to Congress, and never reached Wicker’s office. The senator thanked law enforcement and said an investigation was underway but did not elaborate.
