The Salem Strangler

The season premiere of "20/20" features co-anchor Deborah Roberts' reporting on the murder of college student Claire Gravel, who was found strangled off the side of the road just six miles from her apartment in Salem, Massachusetts. For years, there were no arrests, and even though new evidence was uncovered, the case eventually went cold. That is until 2007, when a mother living in a nearby town was attacked in an eerily similar way to Gravel. As detectives zero in on a suspect, this investigation breathes new life into Gravel's murder case. Roberts goes inside the case and interviews Gravel's family, the victim who survived the 2007 attack, as well as law enforcement officials who helped solve the murder.