(CNN) -- A Texas actress in a troubled marriage was arrested and charged Friday in connection with ricin-tainted letters that were mailed last month to President Barack Obama and New York City Mayor Michael Bloomberg, authorities said. Shannon Richardson, 35, also known as Shannon Rogers and Shannon Guess, initially told the FBI that her husband, Nathaniel, sent the ricin-laced letters, but a polygraph exam found her to be "deceptive" on the matter, court papers said. Investigators found that her computer storage devices contained the text of threatening letters sent to the president, but the couple's computer records show her husband...