Police Find 49 Bodies by a Highway in Mexico MEXICO CITY - Forty-nine mutilated bodies were found dumped along a highway on Sunday near Monterrey, Mexico's third-largest city, according to officials. The security spokesman for the state of Nuevo León, which includes Monterrey, said that it would be difficult to identify the victims - 6 women and 43 men - because their heads, hands and legs had been cut off. It was not immediately clear when the people were killed; the bodies already showed signs of decay, officials said. A message left near the scene suggested that the extremely violent Zetas drug cartel was responsible. The bodies were found less than a week after officials authorized extending the army's presence in Nuevo León and the neighboring state of Tamaulipas until the end of November. President Felipe Calderón began sending federal troops to fight organized crime syndicates in many parts of the country when he took office in 2006; violence related to the drug cartels and the crackdown on them has claimed more than 50,000 lives, most of them in states like Nuevo León near the American border. The state attorney general, Adrián de la Garza, said the bodies were found in Cadereyta Jiménez, which is just east of Monterrey and 105 miles southwest of McAllen, Tex. Mr. de la Garza said the victims might have been migrants headed for the United States, though he pointed out that some of the bodies had tattoos of the "Santa Muerte," the Mexican skeletal saint of death. As the drug cartels have diversified their activities to include extortion, money laundering and human trafficking, they have taken aim at Central and South Americans passing through Mexico on their way north. Last year, the bodies of 193 people who were believed to have been migrants were discovered in a grave in San Fernando in Tamaulipas. A year earlier, 72 massacred migrants were found in the same area. The Zetas, one of the most ruthless of Mexico's gangs, are believed to have been responsible for both mass killings. The Zetas began as assassins for the powerful Gulf cartel, but split off in 2010 and have been waging a turf war with other criminal gangs, including the Sinaloa cartel, since then. There have been a series of grisly discoveries in Mexico recently, including 23 bodies found in Nuevo Laredo bearing signs of torture, and 18 dismembered bodies found in vans a week later near Guadalajara, Mexico's second-largest city. In September 2011, 26 bodies were dumped in the heart of Guadalajara, and a month later at least 60 bodies were found in Veracruz State. Speaking to reporters on Sunday, Jorge Domene, the Nuevo León state security spokesman, mentioned some of the recent massacres. But he said that the violence was taking place between criminal gangs. "This is not an attack against the civil population," Mr. Domene said.