S1, E11: A serial killer who targets college girls has struck again, and the town of Neptune is terrified. Keith, who previously worked on the case, temporarily returns to the sheriff's department to help catch the killer. Meanwhile, Veronica's own investigative caseload (and income) increases as she conducts background checks to get the dirt, on her schoolmates' parents. But for her computer geek friend, Mac (recurring guest star TINA MAJORINO), the information Veronica learns may have life-altering consequences.