Photos: Actress arrested in ricin case – Shannon Richardson, a Texas actress, was sentenced Wednesday, July 16, to 18 years in prison, after admitting last year that she sent ricin-tainted letters to President Barack Obama and then-New York City Mayor Michael Bloomberg. Hide Caption 1 of 6

Photos: Actress arrested in ricin case – Richardson, also known as Shannon Rogers Guess, was accused of possessing a toxin for use as a weapon. She faced up to life in prison before the prosecution and defense reached a plea deal under which she would serve no more than 18 years. Hide Caption 2 of 6

Photos: Actress arrested in ricin case – In May 2013, the letters were mailed from Shreveport, Louisiana, to Obama, Bloomberg and to a foundation founded by Bloomberg that opposes illegal guns. Hide Caption 3 of 6

Photos: Actress arrested in ricin case – Law enforcement officials said they believe Richardson may have sent the letters because she was angry at her husband. Hide Caption 4 of 6

Photos: Actress arrested in ricin case – Investigators found that her computer storage devices contained the text of threatening letters sent to the president, according to an FBI affidavit. Hide Caption 5 of 6