Texas actress Shannon Guess Richardson, 36, who plead guilty in December to sending President Barack Obama ricin in a letter, was sentenced to 18 years in prison Wednesday, according to the U.S. attorney’s office.

Richardson, who also sent a ricin-laced letter to then-New York Mayor Michael Bloomberg, was also given a $367,000 fine. The The Walking Dead bit player was originally looking at life, but cut a deal to get the 18 years.

Records show that Richardson ordered castor beans and lye, synthesized the ricin, and mailed the letters from Shreveport, Louisiana, in May 2013.

Ricin is a highly toxic, naturally occurring lectin (a carbohydrate-binding protein) produced in the seeds of the castor oil plant Ricinus communis. A dose the size of a few grains of sand can kill an adult, and acts as a toxin by inhibiting protein synthesis. Ricin causes severe diarrhea, and victims can die of circulatory shock. Symptoms typically don’t present themselves for a few hours to a full day after exposure, and most victims die within 3-5 days. Survivors typically experience long-term organ damage.

Twitter ricin humor:

The Texas woman who sent ricin-laced letters to Obama had a minor acting role in "The Walking Dead." She should have been in "Breaking Bad."

— Keating Thomas (@keatingthomas) July 16, 2014

Most acute ricin poisoning cases due to overdose are attributed to the ingestion of whole castor oil beans. Just 5-20 beans can be fatal to an adult, though those who survive experience nausea, diarrhea, tachycardia, hypotension and seizures persisting for up to a week.

Ricin is listed as a schedule 1 controlled substance under both the 1972 Biological Weapons Convention and the 1997 Chemical Weapons Convention, and has been viewed as a domestic threat, as castor beans are easy to come by.

The FBI revealed that the ricin letters contained very small amounts of the substance, and were intercepted before causing any harm. The letters also issued a threat – “You will have to kill me and my family before you get my guns. The right to bear arms is my constitutional God-given right. What’s in this letter is nothing compared to what I’ve got planned for you.”

Image via Youtube