The jury has been selected in the murder trial of a Dover man prosecutors say raped and killed a 19-year-old college student after his former girlfriend lured her to their apartment. Authorities say 31-year-old Seth Mazzaglia strangled UNH sophomore “Lizzi” Marriott in 2012. Prosecutors say Mazzaglia and McDonough dumped her body into the Piscataqua River. It hasn’t been found. The trial is scheduled to start May 27.