Second Suspicious Letter Sent to President Obama

In addition to the ricin-laced letter sent to Sen. Wicker

The U.S. Secret Service is investigating a letter containing a "suspicious substance" that was addressed to President Obama, the agency confirmed on Wednesday.

The letter was sent to Obama on Tuesday,and was intercepted at the White House mail screening facility, according to Secret Service spokesman Brian Leary.

The White House mail screening facility is a remote facility, not located near the White House complex, Leary said.