US President Barack Obama speaks on the Boston Marathon bombings on April 16, 2013 in the Brady Briefing Room of the White House (Getty Images)
WASHINGTON -- The U.S. Secret Service says it has intercepted a letter addressed to President Barack Obama that contained a "suspicious substance."
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.
Officials said a second letter sent to the Senate has been intercepted at that same offsite facility and tested positive for ricin.
Tensions have been high in Washington and across the country since the deadly bombings on Monday at the Boston Marathon that killed three people and injured more than 170.