Skirmishes between the Zetas and the Gulf cartel have been brewing for years, but war was declared in late January after Sergio Peña, a top lieutenant to Miguel Trevino Morales, was gunned down in Matamoros by an alleged member of the Gulf cartel. Moreover, the sentencing last week in Houston of Osiel Cardenas to 25 years in U.S. federal prison "opened the flood gates," said Valle.
"The rather light sentence suggest that Cardenas sang, gave names, details and that's only contributed to the mayhem," Valle added.
Ciudad Juárez, some 600 miles up the border from Nuevo Laredo, remains by far the most violent city in Mexico, accounting for more than 450 killings this year, and more than 4,650 since January 2008. Tamauilipas state, however, is a powder keg. This is home to the Gulf cartel and the Zetas. Some of the members were trained as elite special forces operatives by the U.S. and other foreign governments before Cardenas lured them into deserting and forming their mercenary army.
In the last few weeks, according to U.S. intelligence, the Gulf cartel, with the backing of La Familia from Michoacan and the Sinaloa cartel led by Joaquin "El Chapo" Guzman, the most wanted criminal in Mexico, decided to "wipe out the Zetas, get them out of the way," Valle said.
"The glue was Osiel, the 25-year sentence was the trigger he is not coming back," said Alberto Islas, an analyst on organized crime in Mexico City.