Evaluation Day

It's evaluation day for the staff, but Grissom's evaluations take a back seat when a severed head, sans body, is found in a car's trunk. Meanwhile, Sara and Nick investigate when a body turns up in the desert, and it happens to be missing the head. Warrick is sent to investigate things at the juvenile detention center after a teen is found murdered. The only witness to the death is the young man James, whom Warrick identified in episode 3, as guilty of a hit and run and promised to look after.