A second ransom note received by a Tucson, Arizona, television station following the disappearance of Nancy Guthrie said she died shortly after her abduction.
The men who found her say her van got stuck on the trail, so she got out and fell into mud that she said was "like quicksand."
An independent search is underway for Nancy Guthrie's remains near the border following an anonymous tip about the whereabouts of her body, though authorities say there is no evidence to verify the claim.
Forensic evidence recovered from the electronic devices of Lynette Hooker's husband, Brian Hooker, have led investigators to new areas of interest.
The U.S. Coast Guard has seized the boat used by Americans Brian and Lynette Hooker.