James Everett Dutschke has pleaded guilty to sending President Barack Obama ricin-tainted letters.
The 42-year-old Mississippi man admitted he also sent poisoned letters to Republican Senator Roger Wicker and a Mississippi judge.
James Everett Dutschke is expected to be sentenced to 25 years in prison as part of a plea agreement with prosecutors.
Police initially arrested a local Elvis impersonator in the case but later determined James Everett Dutschke had framed him.
The two had known each other but had developed a rivalry and enmity.
Ricin is a naturally occurring protein found in the castor oil plant that is highly toxic. It is 6,000 times more poisonous than cyanide.
The letters to Barack Obama and Roger Wicker were intercepted. The Mississippi judge received the ricin-tainted letter, but she was not harmed.
In separate cases last year, letters containing ricin were sent to former New York Mayor Michael Bloomberg, to President Barack Obama and to the CIA.
[youtube jcJdTm6Q1fY 650]