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 about a mile from Guthrie’s home on Wednesday morning, knocking on doors and searching through the dense desert terrain filled with cactus, bushes and boulders. Several hundred detectives and agents are now assigned to the investigation, which is expanding in the Tucson area, the Pima County Sheriff’s Department said.

A day earlier, authorities said they had stopped a man near the U.S.-Mexico border, just hours after the FBI released videos of a person wearing a gun holster, ski mask and backpack and approaching Nancy Guthrie’s home in Tucson. The man told media outlets early Wednesday that he was released after several hours and had nothing to do with Guthrie’s disappearance last week.

Authoriti...