Mexico’s armed forces killed one of the nation’s top drug kingpins this weekend, but signs that the death will lead to more violence and turf battles have terrified residents.
Antonio Ezequiel Cardenas Guillen, also known as “Tony Tormenta,” the highest-profile leader of the powerful Gulf Cartel, was gunned down in the northern state of Tamaulipas after hours of street battles resembling urban warfare.

President Obama called Mexican President Felipe Calderón to congratulate him for bringing down the cartel leader and the two governments said Mr. Cardenas’s death was a major blow to organized crime. The US State Department had targeted the drug lord with a $5 million bounty after he’d inherited the cartel from his brother, Osiel Cardenas Guillen, following his arrest in 2003.

Cardenas’s death comes as Mexico has scored a string of victories against major drug figures over the past year, including the December 2009 killing of Arturo Beltran Leyva, leader of the Beltran Leyva criminal syndicate; the August arrest of the man fighting to replace him, American-born Edgar Valdez Villarreal, known as “La Barbie"; and the July killing of Ignacio “Nacho” Coronel, a top boss in the Sinaloa cartel.

The slaying of Cardenas in effect destroyed the powerful Cardenas family legacy that, at its height, ruled one of the nation's top cartels. But it may have also emboldened the more ruthless and powerful Zetas, formed by ex-military that broke away from the Gulf Cartel and has unleashed beheadings and massacres arguably more brutal than any other drug gang. The group has been tied to the butchering of 72 South and Central American migrants in August.

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“The reality is that [Zetas leader] Heriberto Lazcano, 'El Lazca,' is the top guy in Tamaulipas. He and his Zetas will now likely have even more power in the region, and sadly this probably will result in more extortion, kidnapping, and fear for the people of Tamaulipas,” said Malcolm Beith, a freelance journalist and author of a book on the drug war, “The Last Narco.”

Some experts have questioned the government’s method of taking down cartel heads, saying it leads to bloody fights for succession and the splintering of cartels into many crime groups.

“They cut off one head and many more grow back,” says Humberto Palomares, a researcher at the Colegio de Frontera Norte (College of the North Border) in Nuevo Laredo, Mexico. For example, Osiel Cardenas’s arrest only led to the eventual split between the Zetas and the Gulf Cartel, according to Mr. Palomares.