Old Ghosts - S4.E4

An obsessed Malone is haunted by an unsolved case in Georgia concerning several teenaged girls who were slain with a knife 15 years ago, and when more older victims are suddenly found - marked with slashes on their bodies -- his focus zeroes in on their original prime suspect who has resurfaced in the area. Once he has the VCTF team on board, he enlists Rachel's help to connect the two crime sprees but his decision to exhume the earlier victims understandably draws the wrath of their ever-grieving parents.