William Clark Crumpacker, 37, vanished on the night of March 16, 1998, while spending the night on his boat with his two young sons at Lake Travis, Texas. He told the children he was going for a swim to clean off, left the boat and never returned. The next morning the boys found him gone and a blue bath towel was partially wrapped around a bush on the shore, suggesting he may have reached land after the swim.

Crumpacker was an experienced boater and swimmer and worked as a marketing manager for Dell after an earlier position with Compaq in Houston. His anchored boat had both batteries dead and was near Little Devils Cove in water about 35 feet deep. Investigators believe he likely succumbed to hypothermia in roughly 55-degree water and drowned, but his body was never recovered and the case remains classified as Lost/Injured Missing.

Anyone who was at Lake Travis around Little Devils Cove on March 16–17, 1998, or who remembers seeing a blue bath towel or activity near shore that night is asked to come forward.