Continuity mistake: In the scene when the investigators at the police station realize who the killer is, the deputy enters and says that a revolver is missing. However, when Cory pulls out the weapon in the woods, he is holding a semi-automatic pistol. The deputy would know the difference between the two, but still uses the wrong term (a revolver may be referred to as a pistol, but an automatic like Cory had stolen can never be called a "revolver", as the chamber does not revolve).
Continuity mistake: In the scene just after Gideon talks to Cherish's mother we see him start to walk toward the rest of the team. In the wide shot we see Reid standing with his hands in his pockets and jacket open, we then see him close his jacket and cross his arms as Gideon gets closer, but in the very next shot (the close up on Reid) we see his jacket open and his arms at his side once more.