An actress who has appeared in The Walking Dead and The Vampire Diaries has pleaded guilty to sending ricin-laced letters to U.S. President Barack Obama and outgoing New York Mayor Michael Bloomberg.

Shannon Rogers Richardson was arrested in June (13) amid allegations she sent three 'poisoned' notes to Obama, Bloomberg and his colleague Mark Glaze, threatening harm if they continued to push for tougher gun control laws.

The actress, who also goes by Shannon Guess Richardson, originally tried to pin the blame on her estranged husband, Nathaniel Richardson, who filed for divorce in June (13), but she has now taken responsibility for the crimes.

Richardson entered the guilty plea on Tuesday (10Dec13) in Texarkana, Texas.