A Texas woman pleaded guilty Tuesday to sending letters containing ricin to President Obama and New York Mayor Michael Bloomberg earlier this year. 

Shannon Guess Richardson, a former actress, pleaded guilty in federal court after being charged with possessing and producing a biological toxin.

She sent the letters in May and was arrested in June.

Her attorney, Tonda Curry, arranged a deal for Richardson that would limit her sentence to a maximum of 18 years in prison, according to The Associated Press

At the time the letters were sent, FBI officials said they had found “very low concentrations” of ricin on the letters. 

Richardson played minor characters on a few TV series, including “The Walking Dead” and “The Vampire Diaries.”