Cadaver dogs discovered bones in a shallow grave in the desert on Wednesday. Authorities said they don't know yet if the remains belong to Powell, who was reported missing in December 2009.
Her husband Josh Powell remains the only person of interest in the case, but he has never been arrested or charged.
Authorities returned to the discovery site on Thursday morning. The site is about 135 miles southwest of Powell's West Valley City home, where she was last seen.
The area also is just about 30 miles south of where Powell's husband, Josh Powell, told police he took his two young children camping on the night his wife vanished.
The Associated Press contributed to this report.
