WHITE HOUSE: FBI 'Has A Lead' On Suspicious Letter Sent To President Obama

White House Press Secretary Jay Carney confirmed Wednesday that the Secret Service has found a letter addressed to Obama containing a "suspicious substance."

Carney said that the "FBI has a lead" in the investigation into who sent the letter. A similar letter was sent to Mississippi Republican Sen. Roger Wicker Tuesday, which tested positive for the poison ricin.

Obama was briefed on the letters Tuesday night.

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