Witch Hunt - S4-E6
Visible crew/equipment: When Gibbs is searching the room he walks into the bathroom, turns the light on and leaves. Look in the mirror to see the reflection of the camera man's arm. (00:15:00)
Witch Hunt - S4-E6
Visible crew/equipment: When Gibbs gets the phone call in interrogation, a piece of filming equipment appears in shot on the left hand side of the screen. (00:34:10)
Witch Hunt - S4-E6
Visible crew/equipment: Just as Abby identifies the John Doe, from the angle behind her there is a crewman in a red shirt in shot over her right shoulder. (00:34:50)
Answer: I hadn't seen the backdoor pilots yet but while it wasn't explicitly stated, at least onscreen, I heard somewhere Vivian got either fired from NCIS due to jeopardizing a case, got resigned from the agency, or transferred to the FBI.
Raykvega423