4. Lost Time

S4 E4: The backpack and ID of a missing college coed, Skye Petersen, are suddenly dropped off at a thrift store seven years after Jack and the legal system-determined she was murdered by her married professor. She had just ended an affair with the professor, so the team decides to reopen the case. Jack fears that he may have elicited a wrongful murder confession during an intense interrogation with the professor.