Question: Who was the Republican Senator of Mississippi that has been in office since 2007, who in 2013 was a letter addressed to that contained ricin?
Sentence (from "April 2013 ricin letters"): On April 15, 2013, an envelope that preliminarily tested positive for ricin, a highly toxic protein, was intercepted at the US Capitol's off-site mail facility in Washington, D.C. According to reports, the envelope was addressed to the office of Mississippi Republican Senator Roger Wicker.
Relevant evidence: Yes