Ricin-Laced Letter to Senator Intercepted in Prince George's County

Federal investigators searched a mail sorting facility in Prince George's County Tuesday night to learn more about a ricin-laced letter sent to Mississippi Sen. Roger Wicker, according to The Washington Post.

The U.S. Senate's mail sorting operation is located at 6330 Columbia Park Road in Landover. An FBI spokesperson would not divulge the location of the bureau's investigation, but several outlets published images of hazmat trucks parked outside of the Landover facility on Tuesday.

The discovery of the letter coincided with a second envelope addressed to President Barack Obama intercepted at White House mail processing site on the grounds of the Anacostia Naval Station. That letter was found to contain "a granular substance that preliminarily tested positive for ricin."

The envelope was quarantined by the Secret Service and an investigation was initiated, according to the FBI.

The government will test any mail facility where suspicious powder is found, the bureau noted, but the substance is only officially identified as ricin once it is analyzed in an accredited labratory.

The substance is currently undergoing tests, according to the FBI, which can take up to 48 hours.

The bureau stated that there is no indication that the letters are related to the attack in Boston.