Search for Nancy Guthrie descends onto rugged desert terrain

Fresh surveillance images from Nancy Guthrie’s porch the night she went missing, coupled with intense police activity across Arizona and the detention of a man had raised hopes that authorities were nearing a major break.

By then the man was released after questioning, leaving it unclear Wednesday where the investigation stood into last week’s disappearance of Guthrie, the 84-year-old mother of “Today” show host Savannah Guthrie.

FBI agents fanned out across a neighborhood...