The death of a lone undercover operative in a federal crackdown on the black market for ancient American Indian artifacts has thrown plans for a first trial into doubt.

U.S. Attorney for Colorado David Gaouette says he's reviewing the evidence left for a trial that was to start March 29.

Antiquities dealer Robert B. Knowlton is accused of selling a prehistoric pipe and two knives to the Utah businessman who secretly recorded hundreds of hours of videotaped sales with 26 defendants in Colorado, Utah, and New Mexico.

Gaouette says he's reviewing ways to use the videotape without live testimony from Ted Gardiner, who shot himself Monday after a police standoff. Gaouette wasn't certain if Knowlton's trial will start as scheduled.