TUCSON, Ariz. — The chances that Nancy Guthrie was brought across the southern border into Mexico remain low due to a number of factors, including the enhanced security measures being utilized by federal authorities there, one expert said. 

The border wall near Nogales, Arizona, some 60 miles from Tucson, the city where Guthrie resides, is several feet high and lined with barbed wire fencing for miles well beyond the city in both directions, said retired NYPD Lt. Darrin Porcher.

“When we look at how the border wall is aligned, it seems very difficult to get across from the United States into Mexico because this is not a porus environment,” Porcher told Fox News Digital at the border crossing that separates Nogales, Ariz., from Nogales, Sonora, Mexico.

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Porcher also noted the surveillance cameras that line the border and the U.S. Border Patrol agents staked out in vehicles a few hundred yards apart in some areas. 

Authorities have said there is no evidence that Guthrie, 84, was taken across the southern border, but experts have noted the federal protocols automatically come into play regarding her alleged kidnapping.  

Despite the logistical problems of taking a captive across the border, Porcher said law enforcement should have immediately begun looking into the possibility, given Mexico’s proximity to Guthrie’s home. 

“I believe this is something that law enforcement should have attached too immediately within the first 72 hours, because it seems as if they were coming into a brick wall and not gaining any solutions as it relates to a kidnapping occurring,” he said. 

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“This is a point of contention that should have been addressed early on in the investigation,” he added. 

Mexican authorities in Sonora have disputed claims that the FBI has asked them for help in the search for Guthrie , who was last seen at her home in the Catalina Foothills, Ariz., the unincorporated community where Nancy Guthrie’s home is located.

The office of Sonora Attorney General Gustavo Rómulo Salas Chávez wrote on the social platform X in Spanish that “it has not received a formal request for collaboration in the case of a missing person in Arizona,” referring to Guthrie.

“To date, this institution has not received any formal request for collaboration, assistance, or exchange of information from U.S. authorities or Mexican federal agencies in relation to said case,” Chávez’s office added. 

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Pima County Chris Nanos has said that investigators have had any indication that Guthrie  was taken across the border. 

“We know where Mexico is in relationship to this, and it’s a possibility. But no, we have nothing to indicate that,” he previously said.