Did A Walking Dead Zombie Send Ricin-Laced Letters To Obama And Bloomberg? A Texas couple are blaming each other for the new batch of ricin-laced letters sent to President Obama and New York Mayor Mike Bloomberg, and one of them just happens to have played a zombie on The Walking Dead. The New York Post reports that Nathaniel Richardson was brought in for questioning in the case, but was later set free when he claimed it was his pregnant wife, actress Shannon Guess, who had actually sent the poison letters. The FBI was tipped off to Richardson after Guess called them saying she found ricin in her refrigerator, along with directions on âhow to make ricinâ and Google searches on Obama and Bloomberg. Guess, seen on a website for The Walking Dead (via Gawker) and in a separate promotional shot in a bikini holding a rifle (via Uproxx), has also appeared in bit parts on television series like Vampire Diaries, Drop Dead Diva and others.