One case concerns a serial killer who phones police confessing he murdered someone; he is captured a few blocks from the pay phone. To convict him, they need to prove there's been a murder (a body would help), tie it to the perp, and motive might help. Led to the disposal place of one victim, a tool marks expert links the bone's cut marks to the killer. But is he sane? Second, a cold case squad is working on identifying the young woman whose bones and clothes have been discovered abandoned in a woody area.