Deibert was last seen off the coast of Lewes, Delaware on February 4, 2007. He was a federal ship's pilot with the Chesapeake Federal Pilots Association, and had over thirty years' experience sailing. While attempting to board the coal carrier Energy Enterprise late that evening, Deibert fell off the ship's ladder into the water. The water temperature at the time was approximately 39 degrees Fahrenheit. Witnesses threw three life rings into the water to try to help him, but he disappeared.

Deibert lived in Virginia Beach, Virginia in 2007. He is divorced with two children. His body has never been found in spite of an extensive search, but he is presumed lost at sea. He has been declared legally dead.