India, Feb. 4 -- Desperate law enforcement officials in Arizona, searching for Today co-host Savannah Guthrie's mother Nancy, have disclosed that they still have no suspect four days after the 84-year-old's disappearance. They have enlisted the assistance of the FBI to help solve a case on which they appear to be making minimal progress.

Pima County Sheriff Chris Nanos addressed a news conference on Tuesday, stating, "We do not know if multiple people were involved," as he reiterated his appeal for the public's assistance in locating Nancy.

When a reporter inquired about Nancy's whereabouts and the number of people involved in her disappearance, he just said, "no clue."

"We have crime in Tucson all the time," he continued, addressing a...