The FBI And Army Fell Victim To A Twin Falls UFO Prank 75 Yrs AgoThe FBI And Army Fell Victim To A Twin Falls UFO Prank 75 Yrs Ago The joke resulted in a southern Idaho visit from the Army and FBI four days after the alleged Rosewell incident, on July 11. The story didn't get much exposure outside of Idaho.Greg JannettaGreg Jannetta