( 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 could n't have printed them out because he was at work at the time , an FBI arrest affidavit said . On Thursday , Shannon Richardson told investigators she mailed the ricin-tainted letters , but she claimed that her husband typed the letters and forced her to print and mail them , the affidavit said . New poison letters put ricin under microscope . Her husband denied involvement and claimed his wife wanted to end their marriage and leave him , the affidavit said . He told investigators that his wife was `` intentionally misleading '' them , the court papers said . Shannon Richardson is accused of mailing a threatening communication to the president and faces up to 10 years in prison if convicted , according to a statement from U.S. Attorney John M. Bales ' office in Texas . Also on Thursday , Nathaniel Richardson filed for divorce . His wife is pregnant , and the anticipated birth date and sex of the fetus is not known , the divorce lawsuit said . The couple married on October 8 , 2011 , the suit said . Shannon Richardson allegedly also mailed a third letter with the toxin ricin to Mark Glaze , director of Mayors Against Illegal Guns , which was founded and co-chaired by Bloomberg , the FBI arrest affidavit said . The group 's office is in Washington . She made an initial appearance Friday afternoon before U.S. Magistrate Judge Caroline Craven in Texarkana , Texas , the prosecutor said . She was arrested in Mount Pleasant , Texas , authorities said . The three letters were mailed from Shreveport , Louisiana , last month , federal authorities say . The FBI found `` very low concentrations '' of ricin on the letters , a spokesman said last month . Richardson has had minor roles in TV series , including `` The Walking Dead '' and `` The Vampire Diaries . '' A law enforcement official told CNN that investigators believe Richardson sent the letters herself . She was angry at her husband , the official said . CNN reported early in the investigation that the FBI considered Richardson to have serious credibility issues when they began interviewing her . What is ricin ? CNN 's Joe Johns and Joe Sutton contributed to this report .
Shannon Richardson , 35 , initially told FBI her husband sent ricin-tainted letters . But she failed polygraph , and husband said she wanted to end marriage , FBI says . Before her arrest , she allegedly admits to mailing letters , but says husband forced her . Her husband files for divorce ; she 's also pregnant , divorce lawsuit says .