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From four miles up, smuggling along the Mexican border comes in various forms: illegal immigrants sneaking through the brush, a drug-running, ultra-light airplane heading toward Tucson, Ariz., a Black Hawk helicopter corralling a group of border crossers. Those scenes are all seen by a predator remote-controlled aircraft armed with high-powered cameras, CBS News Correspondent Bob Orr reports.
Dave Gasho runs the predators for U.S. Customs and Border Protection at a barren base in Arizona.
Pilots "fly" the planes from a trailer on the tarmac.
"Most people coming across the border are either migrants or drug smugglers," said Gasho. "We don't know who they are. They could be terrorists. They could be people who have intentions of harm against the United States."
Predators are best known for tracking and killing terrorists in Afghanistan and Pakistan.
Here, on the U.S. border, they are used strictly for surveillance.
CBS News spoke with Gasho as a predator watched from above.
"I'm pretty sure they'll be able to tell you're wearing a blue shirt, tan slacks, I'm in a flight suit with a black hat," said Gasho. "They can see that."
Gasho said people trying to sneak across the border would be plainly visible to the drones, giving federal agents an advantage to get in position to intercept them.
Policing the 2,000-mile-long border with Mexico is more than a full-time job for some 17,000 U.S. Border Patrol agents, but the predators help shrink that challenge. They're able to peer miles into Mexico.
For agents like Colleen Agle, the predator serves as high-tech backup.
"They can make a rapid identification and classification of what exactly is there so that we know what kind of law enforcement response we need to make," Agle said.
Three of the aircraft fly along the Mexican border. Two patrol the Canadian border, and one cruises over the Caribbean.
In the last five years, predators have helped net 40,000 pounds of drugs and nab 7,000 illegal immigrants, according to Homeland Security.
"We are expanding the manpower resources," Gasho said.
Gasho wants more pilots to keep the predators flying around the clock, saying nothing else provides this kind of immediate intelligence.
"My boss in Washington, D.C., can log on and say, 'What are we looking at right now?'" Gasho said.
The picture is fed in real time to the command center.
The program is expensive. Each predator costs around $18 million and the aircraft has limits. They are only cleared to fly inside a narrow zone along the border and can't fly at all in bad weather. Still, to Gasho, the air fleet is essential.
"This is sovereign U.S. soil, and I think we need to defend it as such," Gasho said.
And Congress is sold. A fourth predator is on its way to the Mexican border.
More on Drones in U.S.
Errant Drone near D.C. almost Shot Down
U.S. Expands Use of Drones over Southern Border
FAA Pressed to Allow Drone Flights in U.S.