TUCSON, Ariz. — Volunteers in Mexico conducted fresh searches for Nancy Guthrie, the 84-year-old mother of NBC's "Today" host Savannah Guthrie, following an anonymous tip that her remains may be buried in an unmarked grave near a stream close to the U.S. border, though initial efforts yielded no results as the investigation entered its fifth month.

The tip directed attention to the Mariposa area west of Nogales in Sonora, Mexico, prompting the volunteer group Buscando Corazones Nogales to explore the rugged terrain. Ramona Guadalupe Ayala Ortiz, head of the group, said they received the call describing specific details and had previously uncovered more than 25 unmarked graves in the vicinity containing remains of at least 32 individuals during April and May operations.

"We received an anonymous call telling us that the woman's remains were in the Mariposa area — in a grave over a stream," Ayala Ortiz told local media, according to reports. The group returned for additional searches but came up empty for Guthrie, vowing to continue efforts in the region.

Pima County Sheriff's Department officials in Arizona confirmed awareness of the tip but noted they had not been contacted by Mexican authorities. "We are aware of reports regarding an anonymous tip related to the Nancy Guthrie investigation that was provided to a group in Mexico. At this time, we have not been contacted by Mexican authorities," the department stated. "This investigation remains active and ongoing and we will continue to follow up on any credible information."

Guthrie was last seen at her........

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