Police in Tucson are racing against time to find 84-year-old Nancy Guthrie.

”We will not rest”
Nancy Guthrie, the 84-year-old mother of Today co-host Savannah Guthrie, has now been missing for five days, and authorities believe she may have been abducted. So far, no suspects have been identified.

On Wednesday, Savannah and her family made a tearful public plea, urging whoever took their mother to come forward.

”We will not rest,” Savannah Guthrie said in the video. ”Your children will not rest until we are together again.” She also adressed the reports of a ransom note, saying, ”Please reach out to us.”

But catching Nancy Guthrie’s kidnapper could prove extremely difficult. An expert warns that her abductor may never be found, and it all comes down to one troubling factor. Art Del Cueto, a longtime U.S. Customs and Border Protection officer who lives just minutes from Guthrie’s home, told the Daily Mail that the surrounding terrain presents a major obstacle for investigators.

The rugged Tucson landscape
Del Cueto is not involved in the case, but has years of experience tracking individuals through the rugged Tucson landscape.

The area around Guthrie’s home is remote and surrounded by dense desert vegetation, which Del Cueto says could easily conceal someone trying to flee.

“We’re on the southern border. You’re dealing with international crime all the time, and there are just too many variables to rule anything out,” he explained.He added that Tucson’s proximity to Mexico could allow a suspect to disappear quickly, possibly before authorities even have a clear picture of what happened.

“If somebody gets spooked, they can make it into Mexico in under an hour and a half, that’s why authorities may not be sharing everything they know,” Del Cueto said.