Authorities are searching for clues that may lead them to the person seen on Nancy Guthrie's Tucson, Arizona, porch the morning she went missing.

Here's what to know about the DNA evidence collected so far in the investigation into Savannah Guthrie's missing mother and what results are pending.

The search for "Today" anchor Savannah Guthrie's mom Nancy is in its third week as investigators follow every possible lead in the case.

Nancy Guthrie, 84, has been missing for 18 days after she was taken from her Catalina Foothills home, and in the meantime, the sheriff's department released information Wednesday about "biological ...