TEXARKANA, TX—A 35-year-old New Boston, Texas woman has been sentenced to 18 years in federal prison on a biological weapons charge in the Eastern District of Texas, announced U.S. Attorney John M. Bales and Assistant Attorney General for National Security John Carlin today.

On December 10, 2013, Shannon Guess Richardson pleaded guilty to an Information charging her with possession of a toxin for use as a weapon before U.S. Magistrate Judge Caroline M. Craven. Richardson was named in an indictment returned by a federal grand jury on June 27, 2013, charging her with threatening the President of the United States, mailing a threatening letter to New York City Mayor Michael Bloomberg, and mailing a threatening letter to Mark Glaze in Washington, D.C.

Richardson was sentenced to 216 months in federal prison today by U.S. District Judge Michael H. Schneider and ordered to pay restitution in the amount of $367,222.29.

“Today’s sentencing brings an appropriate and just end to what is surely one of our most unusual, even bizarre cases,” said U.S. Attorney Bales. “The investigation was also very challenging and I hope that East Texans are encouraged to know that their East Texas law enforcement proved to be amazingly resourceful, determined and focused in all facets of this prosecution. It was truly a great job.”

According to the information presented in court, during April-May 2013, Richardson made several online purchases of items for the purpose of producing ricin. These supplies included castor bean seeds and sodium hydroxide (lye). Ricin is a biological toxin that can be fatal if ingested, inhaled, or injected. There is no known antidote or cure for ricin poisoning.

Richardson subsequently placed ricin onto threat letters addressed to President Barack Obama, Mayor Michael Bloomberg and Mark Glaze. On May 20, 2013, Richardson mailed the three threatening letters from the New Boston, Texas, Post Office. On May 30, 2013, Richardson traveled to the Shreveport, LA, Police Department and reported that her husband was responsible for the ricin-laced letters.

Richardson was arrested on June 7, 2013, in Mt. Pleasant, Texas, and has been detained since that time.

This case was investigated by the Federal Bureau of Investigation, the U.S. Secret Service, the U.S. Postal Inspection Service, the Texas Department of Public Safety, the New Boston, Texas Police Department, the Shreveport, Louisiana, Police Department and the New York City Police Department. This case was prosecuted by Assistant U.S. Attorneys Frank Coan, Ryan Locker, and Brit Featherston as well as Trial Attorney Jolie Zimmerman of the Justice Department’s National Security Division.