After nearly three weeks without a breakthrough, investigators may soon scale back the search for Savannah Guthrie’s missing mom.

The that the case may shift to a smaller long-term task force model as key leads have come up empty, ABC News reported Friday, citing “sources with knowledge of the case.”

Partial DNA recovered inside 84-year-old Nancy Guthrie’s Tucson home remains unidentified. Authorities have not linked a vehicle to the abduction, and no additional footage has been recovered from her home security system.