Law enforcement officials say a second letter sent to the U.S. Senate has been intercepted and is being tested for poisonous ricin.
Two officials told The Associated Press on Wednesday that the letter was being treated in the same manner as a separate one sent to Mississippi Sen. Roger Wicker and was undergoing field tests.
The U.S. Secret Service says it has intercepted a letter addressed to President Barack Obama that contained a "suspicious substance."
FBI says preliminary test indicates poisonous ricin in letter.
Secret Service spokesman Ed Donovan says the letter was intercepted at a facility away from the White House. He says the letter was received Tuesday.
The letter comes a day after lawmakers said a letter was mailed to Sen. Roger Wicker that tested positive for poisonous ricin. Another senator said police have a suspect in mind.
A potentially poisonous letter, intercepted by officials, was addressed to U.S. Sen. Roger Wicker.
Preliminary field tests confirm the presence of ricin. Senate Majority Leader Harry Reid did not say when the letter was sent.
Lawmakers were informed of the fact at a closed-door briefing about the Boston Marathon bombings.
There's no additional information on who sent the letter or what message may have accompanied the letter.