Volunteers launch a search effort in Mexico for missing American woman Nancy Guthrie after an anonymous tip claims her remains may be in an unmarked grave near the border, according to reports. Multiple outlets say a group that helps locate missing people in Mexico received the tip and then organized searches south of the border. The reports describe the effort as sizable and volunteer-based. One account notes the tip arrives on Wednesday and indicates a possible grave connected to Guthrie, while other reports broadly describe the claim as that her “grave” has been found. Authorities are not described in the provided summaries, and the reports focus on the volunteer organization’s response to the information received. At this stage, the anonymous nature of the tip and the lack of confirmed findings are central to the coverage.