Attorney: Woman in Ricin Case Could Face 18 Years The attorney of a Texas woman who will plead guilty to sending ricin-laced letters to President Barack Obama and New York Mayor Mike Bloomberg says both sides have agreed to a prison sentence of no longer than 18 years. Tonda Curry also said Monday that Shannon Guess Richardson never intended "to harm anyone at all," but wouldn't disclose more about her motivation. Curry says Richardson has agreed to plead guilty to a federal charge of possessing or producing a biological toxin. She said Richardson is "anxious" to admit that she ordered components to make ricin, a powdery substance that can cause respiratory failure if inhaled. Curry says Richardson also wants to turn over others involved in the plot. Richardson was arrested in June after the letters were discovered.