A volunteer search group in northern Mexico has launched a large-scale search for Nancy Guthrie's grave after receiving an anonymous tip.
The tip claimed that the Tucson grandmother, who went missing in February, was buried in an unmarked grave near the US-Mexico border.
Although the search did not uncover any remains linked to Guthrie, organizers say they will continue searching the area and investigating the information they received.
Guthrie, the mother of NBC host Savannah Guthrie, disappeared from her home in the Catalina Foothills area near Tucson, Arizona, during the early hours of February 1.
Authorities have not announced any arrests, and investigators continue to treat the case as a suspected abduction.
