Executive producers behind The Walking Dead and The Vampire Diaries are struggling to remember an actress who appeared on the shows after she was arrested and charged for allegedly mailing letters laced with ricin to U.S. President Barack Obama.

Shannon Rogers Richardson, who lives in Texas, was taken into custody by police on Friday (07Jun13), a week after she alerted officials from the Federal Bureau of Investigation (Fbi) to claims that her estranged husband, Nathaniel Richardson, had sent three notes containing the poison to the White House and to New York City Mayor Michael Bloomberg, threatening harm if they continued to push for tougher gun control laws.

Her army veteran husband was taken into custody for questioning but denied the allegations, instead insisting Rogers Richardson was the one behind the mailings, which were sent from Shreveport, Louisiana on 20 May (13).

On Friday, the actress, who is pregnant, appeared before a judge in Texas on a charge of mailing a threatening communication to the President of the United States. If convicted, she faces up to 10 years in jail.

Rogers Richardson had a non-speaking role as a member of the undead in two episodes in the first season of The Walking Dead, and held a similar role in The Vampire Diaries, according to The Hollywood Reporter, but neither Glen Mazzara, executive producer of the zombie drama, nor the vampire series' Julie Plec can recall her involvement in their shows.

Taking to his Twitter.com page to enquire about the incident, Mazzara writes, "Some actress from (The Walking Dead) sent ricin letters to the Prez (President)? Never heard of her. Anyone know what role she played?"

Replying to his tweet, Plec adds, "If she played an equivalent part to one she supposedly played on (The Vampire Diaries), she was third background from the right. Or something."