What's Eating Gilbert Grissom?

Plot:

When a group of fraternity members find a spot covered by maggots, Grissom investigates the scene and believes a student is providing the flesh to the maggots. Based on the uniform size of the bones and woods, Nick and Grissom believe a mulching machine was used to discard the body, and soon they find evidence in the machine. Based on a fingernail found in a garbage bag, Catherine concludes that the Blue Painter Killer is back. Now the entire team is working on the case.