Reporting from Mexico City — Mexican marines searching a ranch in northern Mexico found the bodies of 72 people who may have been Central and South American migrants kidnapped by the Zetas drug gang, authorities said Wednesday.
Officials said the corpses of 58 men and 14 women were found Tuesday after a daylong search of a rural swath about 90 miles south of Texas in the violent border state of Tamaulipas, a key smuggling corridor where a bloody feud between the Gulf cartel and the Zetas has produced an air of lawlessness and widespread fear. Authorities did not specify a possible motive for the killings, though migrants have been targeted for extortion by criminal groups.
Information remained incomplete and was based largely on the testimony of a migrant from Ecuador who survived the slaughter and helped marines find the site. With a gunshot wound in his neck, the migrant made his way Monday to a highway checkpoint and summoned marines for help.
Navy spokesman Rear Adm. Jose Luis Vergara said the man told marines that 70 or so fellow migrants had been shot to death by members of the Zetas, a drug-trafficking gang notorious for its ruthless methods.
The gang, once the armed wing of the Gulf cartel, now acts on its own and has increasingly branched into migrant smuggling and other criminal enterprises.
Alejandro Poire, spokesman for the government's anti-crime strategy, said authorities had yet to confirm the nationalities of the victims, but that preliminary information indicated they were from El Salvador, Honduras, Brazil and Ecuador.
President Felipe Calderon, interviewed on radio Wednesday, said the slayings showed the "beastliness" of organized crime groups and the need to continue his government's nearly 4-year-old offensive against them.
The incident underscored the chaos along Mexico's northern border and the spreading involvement of drug gangs in an array of illegal activities, including kidnapping, extortion and selling pirated goods.
The deaths also highlight the risks faced by undocumented migrants crossing Mexico for the United States as ruthless drug-trafficking groups elbow further into the smuggling of people. The criminal bands clash with one another over control of smuggling routes and have kidnapped groups of undocumented migrants from competitors.
In July, 21 people died during a gunfight between rival drug and migrant traffickers in the northern state of Sonora, near the Arizona border.
Tens of thousands of migrants, mostly from Central America, make the dangerous trek across Mexico on their way to hoped-for jobs in the United States.
Rights advocates have long criticized Mexico's treatment of migrants, saying they are offered little protection and often targeted by corrupt officials working with smuggling groups. Migrants are often targets of schemes in which they are held on the Mexican side of the border until their relatives pay thousands of dollars in ransom.
Amnesty International said the massacre "once again demonstrates the extreme danger and violence that Central Americans face on their treacherous journey north, as well as Mexican authorities' abject failure to protect them."
Mexican officials on Wednesday said they would work to safeguard the rights of migrants moving across Mexico.
Poire said the episode in Tamaulipas, where hit men have assassinated political candidates, muzzled newspapers and left many residents cowering indoors, was evidence that the federal government's crackdown on drug traffickers has increased pressure on the cartels. He said the groups have been pressed to search for new sources of income and recruits, and prey on migrants from Central and South America to meet some of those needs.
On Monday, marines backed by navy helicopters went to the ranch near the town of San Fernando after receiving the report from the wounded man. Officials said the forces were fired upon by gunmen who fled in a convoy. Three gunmen and a marine died during the shootout.
Marines seized 21 assault rifles, shotguns and rifles, thousands of rounds of ammunition, bulletproof vests and four pickups painted to resemble military vehicles. A minor was detained and handed over to the federal attorney general's office, the navy said.
The bodies were found a day later, several miles away. It was not clear why the victims were slain or whether they were killed at the same time.
Since Calderon announced the crackdown on organized crime in late 2006, drug-related violence nationwide has claimed more than 28,000 lives, mainly as a result of fighting between rival trafficking groups.
In recent months, dump sites around the country have yielded scores of dead attributed to the drug war. In July, authorities found 51 bodies in a field outside the northern city of Monterrey, which has witnessed severe drug violence. Beginning in May, 55 bodies were recovered from a former mine in Taxco, in southern Mexico.
This week, officials said they had pulled at least nine bodies from an abandoned mine in Hidalgo state, outside Mexico city.