It could have been a scenario straight out of a Hollywood script.

On Tuesday, November 4, around 10 in the morning, Supervisory Border Patrol Agent Guy Good answers the phone at the U.S. Customs and Border Protection office in Casa Grande, a Border Patrol station near Tucson, Ariz. Highway Patrol officers from the state's Department of Public Safety need help, and they need it fast. An accident has been reported at mile post 187 north of Casa Grande, a rollover they think, and 4 people might be dead.

Good calls his team together: Border Patrol Agents Jason Lowery, Gerardo Durazo, and Mike Leal, who partners with a K-9 named Basco. Lowery and Durazo, both in their twenties, have been friends since they met 3 years ago at the Border Patrol Training Academy. Leal is the more senior member of the group-8 or 9 years on the job, but BASCO, his K-9 partner, is a new addition. BASCO's only been on the job 3 months, but today, the K-9 is going to have a chance to prove his stuff.

The Border Patrol agents arrive at milepost 187, where Highway Patrol officers fill them in: there's been a violent, mid-morning shootout along I-10 outside Phoenix, Ariz.-a highway packed with distracted commuters, soccer moms running errands, and long-haul truckers trying to make time and stay out of trouble. State police tell the agents from Casa Grande the situation there is bad-four dead from gun wounds and three injured-but under control. Ten miles north, however, there's bigger trouble, reports that at least four shooters have abandoned a Dodge minivan and are heading off across the desert. The Border Patrol agents, all of them experienced trackers, leave for the site.

Trouble in the making
The four Border Patrol agents heading up the road won't hear the whole story until the action's over-how a brown F-250 pickup truck, loaded with 20 illegal aliens and heading north toward Phoenix, passes a green Ford Explorer driven by rival gang members on the look-out for hijacking opportunities. A quick U-turn, and the Explorer, driven by the second gang of coyotes, locks on-target. They home in quickly on the F-250 pickup, and, armed with a 9mm and a 38-caliber handgun, the hijackers in the Explorer are ready for action. They commandeer the pickup, replace its drivers with theirs, and shift some of the illegal migrants from the pickup's covered cab into the Explorer.

What the hijackers in the Explorer don't know is this: hidden among the illegal aliens riding in the back of the pickup they've seized is one of the "coyotes" from the first gang. Now traveling undetected in the back of his hijacked pickup, mixed in with a load of panicked Mexican migrants, the smuggler takes out his cell phone, dials his criminal superiors in Phoenix, and reports that the F-250 pickup and its load have been hijacked. Rival gang members, he tells his superiors, are behind the wheel and the pickup is once more moving north toward Phoenix, traveling fast and in tandem with the other gang's green Ford Explorer.

Revenge
In minutes, the smuggling organization waiting in Phoenix for their F-250 pickup and its contents sends out their own "rescue team"-a third team of coyotes-in a gray Dodge minivan. Armed with AK-47 assault rifles and an Intratec Tec-9 assault pistol, these gunmen have a new mission-revenge. When they encounter the green Ford Explorer and the pickup at mile marker 181 on Interstate 10, outside of Phoenix, the shooters open up with the AK-47s from the back of the minivan, spraying the Explorer and the pickup with 50-60 rounds.

The pickup, riddled with bullet holes from front to back, veers off the highway and stops. The driver, one of the hijackers originally traveling in the green Ford Explorer, is killed, along with three Mexican migrants riding in the back of the pickup. The rest of the aliens, some badly wounded, stream out of the pickup and disappear into the desert on the east side of I-10. Immigration and Customs Enforcement (ICE) agents, authorities from the Pinal County Sheriff's office, and the Gila River Indian Police move quickly to round them up and arrest them.

The driver of the green Ford Explorer and another smuggler sitting next to him are also wounded, but the bleeding man in the front passenger seat pushes his partner out from behind the wheel, starts the engine and heads north again. Illegal migrants in the back of the Explorer are wounded as well, but the vehicle continues to weave down the highway at high speed. A federal agent passes the SUV, reports the license plate number, and Highway Patrol Officers intercept the Explorer at Elliot Road and I-10. All the occupants are arrested.

The third group of smugglers, the shooters in the gray Dodge minivan are still speeding north, back to Phoenix. At the intersection of Riggs Road and I-10, at almost the same moment that Border Patrol agents Jason Lowery, Guy Good, Gerardo Durazo, and Mike Leal head out in that direction, the minivan's rear tire blows. The shooters abandon the vehicle and, desperate, stumble out onto the road and start moving north, into the desert.

When Lowery, Good, Durazo and Leal arrive, the only thing they see are footprints in the dirt.

That's all they need.

Lowery's heart is pumping. He and Durazo aren't rookies, but this pursuit is one of the most dangerous the men have mounted. Later, Lowery remembers exactly what he was thinking when his boots hit the ground and the team went into action-"Let's go get 'em!"

When we began tracking the shooters," says Agent Guy Good, " there was a lot going on. The air was filled with helicopters, mostly news people. The Sheriff's office had their own people fanning out in different directions. But Basco and Agent Leal locked onto the trail where it began, right next to the abandoned minivan, and we just kept following those tracks."

Years of tracking experience have taught the four Border Patrol agents critical lessons. Concentration. Persistence. Confidence in skills and techniques they know works better than the latest technology. The scene is chaotic: wind and dust from the choppers whirling overhead, the shouts of officers in pursuit of armed and dangerous gunmen, and the noise of vehicles passing by or pulling off the highway to unload more law enforcement officers and equipment.

The Border Patrol team hears very little of it. Agent Leal and his canine Basco are moving close to the ground, and despite all the activity in the air, Agents Lowery, Good, and Durazo keep their eyes down, tracking steadily from one footprint to the next, blocking everything else out.

As the Border Patrol agents move across the desert toward an area covered with thick brush, the noise lessens. Good's GPS device tells him they are exactly 1.1 miles from the first footprint alongside the Dodge minivan. Sheriff's officers, thinking the gunman may have backtracked, begin to move in a different direction, back toward the interstate, and the news helicopters follow them. Suddenly, Basco alerts, and there they are-four gunmen crouched under heavy brush, trying to hide from the helicopters overhead and air surveillance.

Tracking is what we do for a living
The shooters are exactly where Leal, Good, Lowery and Durazo expect to find them-at the end of the trail they've left in the desert dirt. The Border Patrol agents arrest the gunmen, signal to a helicopter in the distance, and by the time the news people arrive and the Sheriff's officers cover the 2 miles between them and the suspects' location, the shooters are handcuffed and lying face-down on the desert floor.

"Tracking is what we do for a living," says Agent Good. "This situation was a little more challenging, because we knew the suspects had already killed four people. They were dangerous. But the tracking skills that led us to the shooters were the same ones we bring to the job day after day."

The four gunmen CBP Border Patrol agents apprehended on November 4 are currently in custody and charged with homicide. Sheriff's officers report they found two Norinko rifles and one Intratec Tec-9 assault pistol in the Dodge minivan the shooters abandoned before taking off into the desert. The 30 round magazine of one rifle was empty; the other had expended approximately 20-25 rounds. The Tec-9, which the shooters had also left behind, was fully loaded with a thirty round magazine.

Authorities in Phoenix report that hijackings, assaults and violent encounters between rival smuggling gangs are increasing along the corridors between Phoenix and Tucson. The first shootout between coyote gangs occurred four years ago at an auto parts store in Phoenix, and at least a dozen freeway hijackings have occurred during the past two months, six involving shootings. Today, tighter security at the border is raising the stakes for everyone involved: migrants who paid their coyote guides $250 to smuggle them across the border a few years ago are now forking over as much as $1500 per person, and as the money grows, so do the risks.

The dangers that once made an illegal crossing with one guide, or coyote, so dangerous-the threat of abandonment and death in a desert environment-are now compounded by the possibility that rival gangs of smugglers may kidnap another coyote's human cargo and demand ransom from family members back in Mexico. For undocumented aliens, the odds of finding themselves in a no-man's land are growing daily: if they aren't abandoned and left to die in the desert, they're just as likely to find themselves caught in the middle of a fire fight between rival gangs.

CBP Border Patrol agents say their part in combating the growing violence and migrant smuggling is certain to grow; reportedly, authorities are talking about creating a special federal, state and local task force to focus on the problem in Arizona. What is clear is that the expert tracking skills Border Patrol agents are already bringing to this effort are making a critical difference, especially when the only trail left to follow is a line of footprints in the sand.