In the interrogation room, Olivia lays out photos of 3 victims in front of Nicholas Boone. The third shows a body they have not yet found. The victim in the striped blue shirt is not found until later at the waterfront after talking to Mako.
When Dunham is first questioning Nicholas Boone about the two deaths, she shows him two pictures of the two bodies. First of the second victim, and another picture, which isn't identified. Later in the episode, Olivia and Peter have found where the second victim's car was abandoned by the killer. There they find another victim, and both the scene and the victim match the body in the second photograph from earlier in the episode, despite the fact that they just discovered the body.