The Federal Bureau of Investigation disclosed Thursday that a "suspicious" letter addressed to President Barack Obama was intercepted at an off-site White House mail facility.
Lindsay Godwin, a spokesperson for the FBI's Washington, D.C., field office, told U.S. News that the bureau hasn't yet confirmed if the letter contained ricin. Tests for ricin usually take two days to process.
WNBC-TV reports that the letter contains the same pro-gun rights spiel as letters discovered Friday near New York City Mayor Michael Bloomberg's office and on Sunday at the Washington headquarters of Bloomberg's gun control advocacy group Mayors Against Illegal Guns.
The two other threatening letters tested positive for ricin, which is made using castor beans. The poison is generally not lethal unless it is consumed.
All three letters were postmarked on May 20 in Shreveport, La., according to WNBC-TV. They reportedly say in part: "You will have to kill me and my family before you get my guns. Anyone wants to come to my house will get shot in the face. The right to bear arms is my constitutional God given right and I will exercise that right till the day I die. What's in this letter is nothing compared to what I've got planned for you."
Godwin was unable to immediately confirm details about the intercepted letter and the FBI did not promptly release an official statement.
Last month three letters postmarked in Memphis, Tenn., tested positive for ricin. They were sent to Obama, Sen. Roger Wicker, R-Miss., and a local Mississippi judge.
An Elvis impersonator was initially charged with sending the April letters, but those charges were dropped and fellow Mississippian James Dutschke, a reported rival of the original suspect, was arrested for the crimes. Investigators believe Dutschke, who is in jail pending trial, attempted to frame the first suspect.