MEXICO CITY — A wounded migrant stumbled into a military checkpoint and led marines to a gruesome scene, what may be the biggest massacre so far in Mexico's bloody drug war: a room strewn with the bodies of 72 fellow travelers, some piled on top of each other, just 100 miles from their goal, the U.S. border.
The 58 men and 14 women were killed, the migrant told investigators Wednesday, by the Zetas cartel, a group of former Mexican army special forces known to extort migrants who pass through its territory.
If authorities corroborate his story, it would be the most horrifying example yet of the plight of migrants trying to cross a country where drug cartels are increasingly scouting shelters and highways, hoping to extort or even recruit vulnerable immigrants.
"It's absolutely terrible and it demands the condemnation of all of our society," said government security spokesman Alejandro Poire.
The Ecuadorean migrant stumbled to the checkpoint on Tuesday, telling the marines he had just escaped from gunmen at a ranch in San Fernando, a town in the northern state of Tamaulipas about 100 miles from Brownsville, Texas.
The Zetas so brutally control some parts of Tamaulipas that even many Mexicans do not dare to travel on the highways in the states.
Many residents in the state tell of loved ones or friends who have disappeared traveling from one town to the next. Many of these kidnappings are never reported for fear that police are in league with the criminals.
The marines scrambled helicopters to raid the ranch, drawing gunfire from cartel gunmen. One marine and three gunmen died in a gunbattle. Then the marines discovered the bodies, some slumped in the chairs where they had been shot, one federal official said.
Poire said the government was in contact with those countries to corroborate the identities of the migrants. Consular officials from Brazil, Ecuador and El Salvador said they had no immediate information on whether any of their citizens were among the dead.
The marines seized 21 assault rifles, shotguns and rifles, and detained a minor, apparently part of the gang.
Authorities said they were trying to determine whether the victims had been killed at the same time — and why. Poire noted that migrants are frequently kidnapped by cartel gunmen demanding money, sometimes contacting relatives in the U.S. to demand ransoms.
Poire also said the government believes cartels are increasingly trying to recruit migrants as foot soldiers — a concern that has also been expressed by U.S. politicians demanding more security at the border.
The government has confirmed at least seven cases of cartels kidnapping groups of migrants so far this year, said Antonio Diaz, an official with the National Migration Institute, a think tank that studies immigration.
But other groups say migrant kidnappings are much more rampant. In its most recent study, the National Human Rights Commission said some 1,600 migrants are kidnapped in Mexico each month. It based its figures on the number of reports it received between September 2008 and February 2009.
Violence along the northeastern border with the U.S. has soared this year since the Zetas broke with their former employer, the Gulf cartel. Authorities say the Gulf cartel has joined forces with its once-bitter enemies, the Sinaloa and La Familia gangs, to destroy the Zetas, who have grown so powerful they now have reach into Central America.
Teresa Delagadillo, who works at the Casa San Juan Diego shelter in Matamoros just across from Brownsville, said she often hears stories about criminal gangs kidnapping and beating migrants to demand money — but never a horror story on the scale of this week's massacre.
"There hadn't been reports that they had killed them," she said.
It was the third time this year that Mexican authorities have discovered large masses of corpses. In the other two cases, investigators believe the bodies were dumped at the sites over a long time.
In May, authorities discovered 55 bodies in an abandoned mine near Taxco, a colonial-era city south of Mexico City that is popular with tourists.
In July, investigators found 51 corpses in two days of digging in a field near a trash dump outside the northern metropolis of Monterrey. Many of those found were believed to have been rival traffickers. But cartels often dispose of the bodies of kidnap victims in such dumping grounds.
The Rev. Alejandro Solalinde, who runs a shelter in the southern state of Oaxaca, where many migrants pass on their way to Tamaulipas, said the Zetas have put informants inside shelters to find out which migrants have relatives in the U.S. — the most lucrative targets for kidnap-extortion schemes.
He said he constantly hears horror stories, including people who "say their companions have been killed with baseball bats in front of the others."
Solalinde said he has been threatened by Zetas demanding access to his shelters.
He said the gangsters told him: "If we kill you, they'll close the shelter and we'll have to look all over for the migrants."
Associated Press writer Alicia A. Caldwell in El Paso, Texas contributed to this report.