Circumstances of Disappearance:
was last seen at an acquaintance's residence in the vicinity of the
23900 block of West Coleman Drive in Congress, Arizona. He left after an argument, and returned to the residence the following morning to collect some
personal items. Riddle did not take his wallet or any other personal items with him when he left his friend's house, and he did not show up for work. He has not been heard from since. His vehicle was located on October 19, 2005 in
the desert near 5 Mile Tank in Congress, Arizona. Several days later, a pair of his shoes were found near where the vehicle had been. The shoes were located in a place that had already been searched. He remains missing and his case remains unsolved.