Prentiss: We saw the bodies, all of them have stress breaks in the same places.
Rossi: That's consistent with years of fight training.
Hotchner: Fight training. You think he's a boxer?
Rossi: It makes sense. A fighter would have the endurance it takes to commit this kind of overkill on this many people with a pipe or with his hands.
Morgan: It would explain why at the first crime scene he lined the bodies up in the corner, like in the ring.
Hotchner: It makes sense about the bloodlust, but what triggered the killings?