Around the middle of the second episode of season 1, "Hung out do dry", agents Gibbs and Todd are in the interrogation room with Lt. Bud Roberts and they are supposed to be the only ones there. However, when Gibbs is to the Lt.'s left with the camera focused on him only, the mirror can be seen and there's the reflection of a man wearing a light blue shirt and possibly jeans standing behind the Lt., when in the previous scenes he obviously wasn't there.