I had done a preflight inspection on one of our HO3-Ss and topped off the tanks. The helicopter was placed on the hard stand for an early morning SAR flight into the Michigan North Woods. I provided the form to the pilot assuring him that everything had been checked and the Helo was ready for flight. The ship was out about fifteen minutes when we got a may day call from the pilot stating that he was out of fuel and autorotating into an open area. When we got to the helicopter the fuel tank was bone dry. I was questioned about the loss of fuel and we checked the entire system and could find no fault.
Later that day I overheard a conversation and discovered that one of our own had gone out with a couple of his civilian friends and drained the 91 Octane fuel into their respective gas tanks. The FBI came in and tested the tanks of every person that had a car that could come on the base. One guy had 91-Octane in his tanks and several of his civilian friends were found to have aviation gasoline in their tanks. That was the last time I ever saw the guy.