Posted: Nov 05, 2015 3:25 PM PST
Updated: Nov 05, 2015 4:02 PM PST
By Som Lisaius

NOGALES, AZ (Tucson News Now) -

Authorities said Mexican drug cartels are recruiting children from both sides of the border to do their dirty work. Not as hit men or smugglers at first, they said, but as potential distractions so that drug loads or human cargo can move through the international border.

Escorted by the U.S. Border Patrol, Tucson News Now visited ground zero of the international conflict between federal law enforcement and illegal smugglers: a 20-foot steel fence separating Nogales, AZ from Nogales, Sonora along the US-Mexico border.

With more than 600,000 arrests in the Tucson Sector since 2000, an alarming trend involves illegal immigrants who have no intention of simply escaping into the United States.

"When somebody is arrested five or six times a month, they're not here to stay, they're out here to work, to work in illegal traffic," Agent Vicente Paco said. "This is very calculated."

In most cases that means drug trafficking and human smuggling: a multi-billion dollar business involving some people who aren't even teenagers when they commit their first offense.

"Each one of these you can tell is a hand print, as people are grabbing and climbing over," said Agent Nicholas Robbs, pointing to prints of all sizes one on the border fence.

The hand prints, often those of children, belong to those who jump the fence, knowing perfectly well they're being watched by the Border Patrol.

"How fast can somebody scale this ... from one side to the other?" Tucson News Now asked.

"It's within seconds," Robbs said.

Just as fast, agents respond and detain the jumpers; situation seemingly averted. But at the same time, others carrying contraband try crossing at another location: a calculated diversion, in this high-stakes game of cat and mouse.

"As we move around, we're being called out like chess pieces, they're communicating," Paco said. "Nobody comes across or jumps over the fence just as fun or as sport - there's always a purpose."

To explain that purpose, Agents Paco and Robbs took Tucson News Now to an elevated location along the border in Nogales known as Hudgins Plateau.

Using binoculars, we could see scouts on the Mexico side watching our every move.

"They monitor our activity just as much as we're monitoring them," Paco said.

This goes hand in hand with juvenile fence jumpers. Some are scouts already. While others take that leap of faith in exchange for fast cash or new clothing.

"That's how they start," Paco said, observing several scouts seated on rooftops in Nogales, Sonora. "They start young monitoring our activity, then they might actually be promoted to actual smugglers."

As we wrapped up our tour with the Border Patrol, an unexpected call came over the radio.

"Only gonna have visual of this guy for another 10 seconds at most," a camera operator said, seeking assistance from agents in the field.

A man spotted on the cameras was seen jumping the wall west of downtown Nogales near the Mariposa Port of Entry.

"Where they're building that new warehouse, you could probably cut him off there," the operator said over the radio.

Taking the call, we arrived on scene in less than three minutes.

With strategically placed cameras on towers and in the mountains near the border, operators led agents within 100 yards of the illegal crosser.

When Agent Robbs closed in and confronted the man hiding under a tree, the subject appeared to be on the phone, talking to somebody who was likely directing him from the other side of the fence.

Bottom line, there are eyes everywhere along the US-Mexico border.

Only this time, as this illegal crosser is taken into custody, it's the guys in green who come out on top.

"If this individual has criminal history and qualifies for criminal prosecution, he might see some time before he gets repatriated back to Mexico," Paco said.