The sentence doesn’t match the crime. Those sentiments came from the family of Lizzie Marriot as they sat in court yesterday to see “Kat” McDonough of Portsmouth enter a guilty plea to charges including hindering apprehension related to the death of the 19-year-old UNH sophomore. McDonough’s sentence was one-and-a-half to four years in prison, and part of the plea deal calls for her to testify when Seth Mazzaglia goes on trial next year. Mazzaglia of Dover has been charged with the murder. Investigators believe McDonough helped Mazzaglia dump Marriott’s body in the Piscataqua River.