Information provided by several individuals arrested recently helped clear up the killings of 36 people, including five reporters, in the eastern Mexican state of Veracruz, a high-level state official said.
The suspects, who belonged to the Jalisco Nueva Generacion drug cartel, confessed to their involvement in the murders, Veracruz Attorney General Amadeo Flores Espinosa said.
Isaias Flores Pineda, suspected of running the cartel's operations in the port city of Veracruz and neighboring Boca del Rio, was arrested last Friday by marines and police, Flores Espinosa said.
Six suspected Jalisco Nueva Generacion gunmen - Claudia Medina Tamariz, Cesar Tejeda Moreno, Pablo Arrieta Andrade, Pedro Temiz Zapot, Javier Benitez Grajales and William Malpica - were arrested along with Flores Pineda, the state AG said.
The suspects confessed to belonging to the cartel and carrying out numerous murders, including those of members of the media, Flores Espinosa said.
One of the suspects told "federal prosecutors that they killed several reporters," Flores Espinosa said.
The information obtained from the suspects helped investigators clear up the killings of Ana Irasema Becerra, who worked for the El Dictamen newspaper; Guillermo Luna, a reporter for the Veracruz News Web site and the daily La Voz del Sureste; and Victor Manuel Baez, who worked for the Milenio Veracruz newspaper, the state AG said.
Investigators were also able to clear up the murders of Gabriel Huge and Esteban Rodriguez, former photographers for the Notiver newspaper and the daily AZ, respectively, Flores Espinosa said.
The journalists were all murdered this year.
Juan Carlos Hernandez Pulido, another suspected Jalisco Nueva Generacion member arrested recently, had several identification cards belonging to slain journalist Ana Irasema Becerra, the state AG said.
The federal Attorney General's Office will be asked to take over the cases since an organized crime group was involved in the killings, Flores Espinosa said.
Federal prosecutors will take over the cases because federal crimes were committed, federal AG's office spokesmen told Efe.
Veracruz has been plagued by a turf war between rival drug cartels that has sent the state's murder rate skyrocketing over the past two years.
The federal government launched "Operation Safe Veracruz" last October in an effort to stem the wave of drug-related violence in the Gulf state.
The Gulf, Los Zetas and Jalisco Nueva Generacion cartels, as well as breakaway members of the once-powerful La Familia Michoacana organization, are fueling the violence in the state.
Veracruz, Mexico's third-most populous state, is coveted as a key drug trafficking corridor to the United States, officials say.
More than 50,000 people, according to official figures, have died in drug-related violence in Mexico since late 2006.
The Movement for Peace with Justice and Dignity, which was founded by human rights activist and poet Javier Sicilia, puts the death toll at 70,000.
The violence has spiked this month, with the Mexico City daily Reforma reporting last Saturday that 231 people were murdered across the country from Aug. 4 to Aug. 10, raising the death toll for the year to 6,309. EFE