WASHINGTON — An envelope addressed to a Mississippi senator twice tested positive Tuesday for ricin, a potentially fatal poison, congressional officials said, heightening concerns about terrorism a day after a bombing killed three people and left more than 170 injured at the Boston Marathon.
One senator, Democrat Claire McCaskill, said authorities have a suspect in the fast-moving case, but she did not say if an arrest had been made. She added the letter was from an individual who frequently writes lawmakers. The FBI and U.S. Capitol Police are both investigating. Both declined to comment.
Terrance W. Gainer, the Senate sergeant-at-arms, said in an emailed message to Senate offices that the envelope sent to Republican Sen. Roger Wicker had no obviously suspicious outside markings and lacked a return address. It bore a postmark from Memphis, Tennessee, where mail from parts of northern Mississippi has long been processed.
Gainer added that there was “no indication that there are other suspect mailings.” Yet he urged caution, and also said the Senate off-site mail facility where the initial tests were performed on the letter will be closed for a few days while the investigation continues.
The letter was discovered at a mail processing plant in Prince George’s County in suburban Maryland, according to Sen. Dick Durbin, the No. 2 Senate Democrat.
Wicker’s office issued a statement saying “any inquiries regarding member security must be directed to the United States Capitol Police.”
But Senate Majority Leader Harry Reid told reporters of the letter, and other lawmakers said they had been provided information by the office of the Senate sergeant-at-arms.
The 61-year-old Wicker was appointed to the Senate in 2007 and won election to a full term two years ago. He previously served a dozen years in the House of Representatives.
He has a solidly conservative voting record, so much so that he drew notice last week when he voted to allow debate to begin on controversial gun control legislation in the Senate..
Milt Leitenberg, a University of Maryland bioterrorism expert, said ricin is a poison derived from the same bean that makes castor oil. He said it must be ingested to be fatal.
“Luckily, this was discovered at the processing centre off premises,” Durbin said. He said all mail to senators is “roasted, toasted, sliced and opened” before it ever gets to them.
One law enforcement official said evidence of ricin appeared on two preliminary field tests of the letter, although such results are not deemed conclusive without further testing. The official spoke on condition of anonymity because the investigation remains active.
The discovery evoked memories of the days after the terrorist attacks of Sept. 11, 2001, when mail laced with anthrax began appearing in post offices, newsrooms and congressional offices.
That included letters sent to Democratic Sen. Tom Daschle, who was Senate majority leader, and Democratic Sen. Patrick Leahy. Two Senate office buildings were closed during that investigation.
Overall, five people died and 17 others became ill. The FBI attributed the attack to a government scientist who committed suicide in 2008.
More immediately, though, the discovery came as lawmakers were demanding answers to the attacks in Boston a day earlier.
There was no evidence of a connection between the bombings and the letter addressed to Wicker, a Mississippi Republican.