A Mississippi man was indicted by a federal grand jury on charges of sending poison-laced letters to United States President Barack Obama and two other officials.
If convicted, James Everett Dutschke, 41, faces maximum possible penalties of life in prison and $250,000 fine.
Dutschke, who was arrested on April 27, is expected to appear in the US district court in Oxford, Mississippi on June 6.
According to the indictment on Monday, Dutschke is charged with one count of knowingly developing, producing, stockpiling, transferring, acquiring, retaining and possessing a biological agent, toxin and delivery system, for use as a weapon and with attempting to do the same. In addition, he was charged with one count of threatening the US president by mail.
He is suspected of mailing ricin-laced letters on April 8 to Obama, Senator Roger Wicker and Lee County Justice Court Judge Sadie Holland.
Dutschke has denied any involvement in the letters.