Spring was last seen when he was dropped off by a family member in the vicinity of Tipton Road and White Water Road in White Water, California at 6:30 a.m. on October 10, 1988. He was carrying an army-green backpack at the time of his disappearance; it contained some food in Tupperware containers. Spring said he was going hiking and camping for a few days and would hitchhike back home or call his family for a ride.

There was a possible sighting of Spring between 12:00 and 1:00 p.m. on the day of his disappearance at the base of the San Jacinto mountains, but he has not been seen since then. An extensive search of the surrounding area turned up no sign of him.

Spring was trained for survival when he was in the United States Army. He worked for the California Department of Forestry at the time of his disappearance, and was also a volunteer firefighter with the Bostonia, California Fire Department. He was interested in a career as a firefighter and had completed his training in that area. His case remains unsolved.