An independent search is underway for Nancy Guthrie's remains near the U.S.-Mexico border following an anonymous tip about the whereabouts of her body, though authorities say there is no evidence to verify the claim.

The Mexican volunteer search group Buscando Corazones Nogales told local media it coordinated the search with local authorities.

In a post on social media, the Pima County Sheriff's Department said it is aware of the reports regarding the anonymous tip, but said it was not contacted by Mexican authorities.