Clark was last seen in Dodge City, Kansas on January 12, 1985. He celebrated his birthday that evening at Stonewalls, a bar in Dodge City, Kansas, and left the bar with two friends shortly before closing time. His friends dropped him off near near Minneola and Beeson Roads; he was supposed to meet a woman from the bar. He was supposed to meet a woman in south Dodge City, Kansas that day. It's unknown whether the meeting took place or who the woman was. Clark has never been heard from again. Six months after his disappearance, someone found his wallet at a salvage yard and anonymously returned it to his family. The wallet contained Clark's work identification and other documents.

Clark was declared legally dead eight years after he went missing. Few details are available in his case, but foul play is suspected. He lived in Minneola, Kansas at the time of his disappearance.