BORDER patrolman Tom Gilbert turns down a dusty, rutted road, drives through several miles of scrub oaks, and brakes to a stop. ``There they are,'' he says, pointing to footprints under the trees. ``There must be at least six of 'em. Came right through here.
``Footprints shine when you look toward the sun,'' Mr. Gilbert explains as he squints toward the west and shields his eyes.
This afternoon, the patrolman is ``sign-cutting'' - using ancient Indian tracking methods to catch drug smugglers along the Mexican border.
His target: Mexican ``mules,'' or couriers, who lug 35-pound sacks of marijuana across the border. The mules bring the marijuana to drop points on the US side.
From there it is trucked to major cities. Each mule gets about $100 per trip across the river, and several mules usually travel together.
We were in ranch country, several miles upriver from Rio Grande City, Texas. Border agents, who prowl remote areas along the Rio Grande, say there are several hot spots for smugglers along the river. This is one of them.
Gilbert, senior agent in charge at the Rio Grande station, teaches classes in sign-cutting to other patrolmen. Today he is showing a reporter how it works.
``These tracks are about four days old,'' the agent explains as he walks down a path where the soil was a fine and dry as talcum powder.
Gilbert stops to examine a footprint. He points to bug tracks across the print - one way of telling the track's age. The track is also marked by several doodlebug holes.
These are the tracks of drug smugglers, Gilbert declares confidently.
``If they're wetbacks, the tracks go just one way,'' he explains. ``If it's dope coming in, the tracks go two ways. Notice - here we have a Converse tennis shoe. Here's the same shoe, going the other way.
``So these tracks go in two directions. Four days old. Probably eight people. And they came through all at once.
``This is a choke point, a place where five trails come together. They start at the river, go two, three miles, then go from here to a housing area.''
Sign-cutting is part of the cat-and-mouse game the Border Patrol plays with smugglers along the remote southern border of the US. When agents find an active trail, like this one, they put it under surveillance.
Today Gilbert decides this is an important trail. He directs two agents, John Clough and David Jennings, to implant an electronic sensor just a few feet from the footpath.
The Rio Grande station has only 44 men to patrol 70 miles of border. Electronic sensors, which can detect the passing footfalls of smugglers, can be a major advantage.
Unfortunately, the tight Border Patrol budget allows this station only a few of the $3,000 sensors. And their sensors are old, and don't always work.
After 15 minutes of digging in the crunchy topsoil, agents Clough and Jennings bury the sensor, and camouflage its antenna with small branches.
Then they turn it on.
One of the agents, weighing perhaps 200 pounds and wearing army-style boots, strides heavily down the trail. The sensor beeps a warning. But when a 170-pound reporter then walks along the trail - nothing.
Frustrated, the patrolmen, sweating under the south Texas sun, dig up the sensor, and plant it again, 30 feet away. Again, the reporter gets past undetected.
Finally, after much digging, moving, and fiddling, it works. But this exercise demonstrates a point made by border patrolmen from Georgia to California: The agency, they say, needs better equipment.
Many of their sensors are years old and constantly need repair. Many Border Patrol vehicles are pushing 100,000 miles - tough miles rolled up on rough terrain. Radios and other electronic equipment usually are not up to date. Due to budget constraints, Congress and the Bush White House won't provide the funds for new gear.
Silvestre Reyes, the chief patrol agent in south Texas, says the lack of equipment hurts.
``There is a tremendous resource out there in technology. We could be much more effective if we were given those types of resources.''
Most needed, according to Mr. Reyes: improved sensors, better communications systems, low-light TV cameras.
Gilbert, with miles of border to watch, says his agents need all the help they can get. Drug smugglers are getting better and better at their jobs.
``I guess we caught all the dumb ones a few years ago,'' he says.
Today, smugglers invest heavily in time and equipment to outsmart the patrol. They don't just come crashing blindly across the border. Smugglers send out scouts, and look for Border Patrol traps.
``They spend as much time looking for us as we spend looking for them - and they're better at it,'' Gilbert explains.
This is America's front line in the war against illegal drugs, the agent observes. But tons of drugs are getting through.
``The dope traffic has really picked up,'' Gilbert says. ``So the Border Patrol's in the dope-fighting business, whether we like it or not.''
One in a series of articles about US border problems.