In the episode 'Born to Kill', the detectives look for a serial killer who picks blonde females, stabs them with two different knives and marks them with the letter 'Y'. In the scene of Emily Proctor coming into the autopsy room to ask about the letter 'Y' engraved onto the victim's chest, the camera faces her, and the body. You can clearly see the 'dead' victim swallow/breathe right before the camera cuts the view to the t.v. screen.