Riggs was last seen in Greenwood, South Carolina on March 4, 2000. He was a senior accounting major at Lander University at the time with plans to graduate that year. He disappeared right before spring break. His mother reported him as a missing person about a week later. One of his associates said Riggs had spoken of plans to travel to Florida, but this has not been confirmed. Riggs has never been heard from again.

Riggs's off-campus apartment was left undisturbed and there was no evidence that a struggle had taken place there. The circumstances surrounding his disappearance are unclear and his case remains unsolved.