The Sum of Her Parts - S3.E5

Years of verbal and physical abuse take a deadly toll when its victim lashes out against his abuser. Unable to kill the actual perpetrator, his mother, the deranged man strikes those who remind him of the wretched woman. The team investigates and Sam accurately assesses the killer's pathology, but mistakenly assumes the man is actin out against his wife, not his mother. When the ages of the victims begins to rise, Sam realizes her error and theorizes that the killer is slowly working up the courage to murder his tormentor. The team then races to find the ill-fated woman before her son can exact his final revenge. B-Story- Sam realizes she and Chloe must begin a new life, and to that end, decides to move into a new home.