The letters were addressed to President Barack Obama, but were intercepted during a mail screening.
Letters addressed to President Barack Obama containing a suspicious substance were intercepted by a White House mail screening facility, although a White House spokesman did not confirm whether there is a connection between the letters and Monday's Boston Marathon bombings.
White House press secretary Jay Carney addressed the press around 12:20 p.m. Wednesday, deferring specific questions on a possible connection to the bombings to the FBI. Carney did, however, acknowledge the concern over the bombings.“There is obviously a lot of interest in the explosions in Boston. I wanted to make clear … that our hearts and prayers go out to the victims.
"The full weight of the federal government is behind this investigation, and as the president said we will find out who did this, we will find out why, and we will bring those responsible to justice.”
One of the letters was sent to a facility that is remote and not located near the White House itself.
The facility routinely identifies letters or parcels that require secondary screening or scientific testing before delivery.
The Secret Service is working closely with Capitol police and the FBI in this investigation.
On Tuesday, authorities intercepted a letter sent to Mississippi Sen. Roger Wicker that preliminary tests showed contained the deadly poison ricin.
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