Now he sits on the same corner, plotting a new way to score crack.
"God is not with me anymore," he says. "I am all alone."
Alone in spirit, perhaps, but in body, Xavier has plenty of company among the growing legions of migrant Mexicans who travel thousands of kilometers to this border city in hope of becoming illegal workers in the U.S.
Instead, they wind up destitute and drug-addicted in this hive of scum and villainy.
"Agua Prieta is now the No. 1 city in Mexico for drugs," says the city's former mayor, Vicente Teran Uribe. (U.S. Drug Enforcement Administration officials might wonder whether Teran Uribe is speaking out of indignation or pride -- when he was elected mayor in 1997, he was on the DEA's list of the top 20 narcotics traffickers in Mexico. The former mayor, who stepped down recently to pursue a seat in the Sonoran legislature, denies any involvement in the drug trade.)
"There is drug business in any border town," Teran Uribe adds, "but the problem of the undocumented people has made the flow of drugs here a flood."
Xavier, 22, left his mother, his wife and his 3-year-old son behind in a Mexico City slum when he took a one-way bus ride to Agua Prieta in September. His plan was to somehow get into the U.S., make his way to Phoenix, get a job, send most of the money he earned back home, then return to his family after a year, maybe two.
His plan was flawed, though, and his luck was bad. He didn't have the $400 that human-flesh smugglers demand for guaranteed passage to Phoenix, and he didn't know anyone in the United States who could pay his debt for him with a wire transfer upon his arrival in Phoenix. So he kept trying to cross the desert himself, and he kept getting caught.
The first time, U.S. Border Patrol agents found him cowering in a ditch, alone, a few feet inside America. Two nights later, he took a more roundabout route with a group he met. They walked many miles in the dark, but Xavier admits he had no idea whether they were in Mexico or the U.S. until he was caught in the lights of a Border Patrol agent's off-road truck.
The next morning, after he'd been processed, loaded on a bus and dumped back in Agua Prieta, Xavier spent 400 of the last 1,000 pesos in his meager travel fund on a gallon of water and his first hit of crack.
He'd been told it would keep him from getting hungry, kill the boredom of waiting and give him courage and energy for his long, hazardous trek.
He'd been told wrong.
The courage and energy wore off after an hour or two, leaving him listless, with hours to go before sunset. So he bought more crack and saved it to smoke along the way, so he was high as the moon when the Border Patrol pulled him out of the scrub brush and sent him back to Mexico a third time.
It's been more than two months since Xavier last heard his son's voice, and two weeks since his last shower. He's wearing the same clothes he had on when he stepped off the bus in September: blue jeans, a Dallas Cowboys stocking cap, and a ski vest torn by a hundred branches, layered over a yellow tee shirt with a big red heart that says "Hollywood is for Lovers."
Xavier smokes as much crack as he can, now, supporting his habit by guiding newly arrived migrants to crack dens in downtown Agua Prieta.
"Mucho roca acqui," he says.
There's a lot of rock here.
And it's cheap. A small piece of crack -- good for about three hits, each of those good for a 20-minute high -- costs Xavier 300 pesos, or about $3.50, less than half the price of the drug in Phoenix. Xavier buys most of his crack from the dealers who shoot pool in a crowded bar called "La Roca": The Rock.
There's a hotel next door with lookouts on the balcony and an Agua Prieta cop in uniform working the front desk.
Xavier claims powder cocaine is cooked down to its more potent rock form in rooms at the hotel, where men with whores by their sides and pistols in their belts keep outsiders off the second floor.
On the street at night, sharply dressed dealers hang out beside gold-rimmed cars with booming stereo systems, openly offering women and drugs to passersby.
There are no official figures on the number of drug addicts in Agua Prieta, just as there are no official numbers on how many thousands of new, would-be immigrants arrive each week to this primary point of entry for Mexicans eager to tap into America's booming economy. Since the border in southeast Arizona has become the prime smuggling corridor from Mexico, local officials say the population of Agua Prieta has grown to perhaps 220,000. The Border Patrol apprehends an average of 1,000 illegals a day in this area.
Most of those who come from the south eventually make it into the United States, but of those who don't, the would-be immigrants turned crackheads are the most pitiable failures. Gaunt, grimy and gap-toothed, they gather in the corners of rubbled, vacant lots and within the concrete skeletons of the dozens of cheap hotels under construction.
"People lose their souls here to the needle and the pipe," says recovering addict Cesar Ortega, 23, an American from San Diego who has lived in Agua Prieta for nearly a year.
"I followed the cheap drugs here," says Ortega, who sells hot pepper Popsicles to drivers stuck in traffic to raise funds for Centro Sida, a local AIDS hospice and outpatient drug-treatment center. "I'll go back home in a few more months, after I've done good to make up for all the bad."
One of the dealers who supplies Centro Sida's future patients is Carlos, who made it from Acapulco to San Diego for two years before he was deported. He wound up in Agua Prieta. Carlos works a corner within earshot of the barking drug dogs at the U.S. border crossing station, selling $35 tickets for a shuttle bus from Agua Prieta to Phoenix, which departs six times daily.
As a sideline, he also sells crack. One of his customers is Manny, who came to Agua Prieta eight months ago from Chihuahua. Wearing a backward Guess Jeans baseball cap and an eager smile, Manny emerges from a train yard with the pink glow of the setting sun at his back, walks up to Carlos and procures a pebble of cocaine in a smooth hand-to-hand transfer.
Manny snags an empty Tecate can from a gutter, peels off the pop-top and uses it to punch a hole in the aluminum. Then he taps some ash from a cigarette over the small hole, puts the crack in the ash, heats it with his cigarette, then dances the flame of a lighter over the bubbling, noxious rock and inhales a deep hit.
The crack lances the pleasure center in Manny's brain. He reels back against a wall and exhales. The sickly sweet smoke drifts slowly toward America, vanishing into the harsh white lights atop towers guarding the entrance to the forbidden promised land.