Envelope with poison sent to Miss. senator

WASHINGTON -- An envelope addressed to Sen. Roger Wicker of Mississippi tested positive yesterday for ricin, a potentially fatal poison, congressional officials said, heightening concerns about terrorism.

Sen. Claire McCaskill of Missouri said authorities have a suspect. The letter was from an individual who frequently writes to lawmakers, she said.

Terrance W. Gainer, the Senate sergeant-at-arms, said the envelope to Wicker, a Republican, had no obviously suspicious outside markings, bore a postmark of Memphis, Tenn., and lacked a return address.

He said the Senate off-site mail facility where initial tests were performed on the letter will be closed 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 (D-Ill.).

Majority Leader Harry Reid told reporters of the letter.

"Luckily, this was discovered at the processing center off premises," Durbin said. He said all mail to senators is "roasted, toasted, sliced and opened" before it ever gets to them.

In the days after the Sept. 11, 2001, attacks, mail laced with anthrax appeared in newsrooms and congressional offices. Five people died and 17 others became ill. The FBI attributed it to a government scientist who committed suicide in 2008. -- AP