The remains of nine of the 27 peasants massacred by Mexico's Los Zetas cartel in May in northern Guatemala were exhumed so they can be released to relatives, officials said.

The exhumations were requested by prosecutors, Judge Carol Patricia Flores said.

Flores traveled on Monday to La Libertad, a city in the northern province of Peten, to oversee the exhumations, which were authorized on Dec. 2, radio reports said.

The 27 farmworkers were massacred by Los Zetas on May 15 at the Los Cocos ranch outside La Libertad.

The exhumations were authorized because the remains of nine male victims were identified using fingerprints, DNA and other information gathered by the National Forensic Science Institute, Flores said.

The remains of Felipe de la Cruz, Reyes Valdez Gomez, Santiago Canan Aquino Perez, Juan Huales, Magdaleno Garcia, Ezequiel Barillas and brothers Jose, Elfido and Dimas Vasquez were identified by officials, the judge said.

A total of 12 of the 27 victims have now been identified.

The remains of brothers Jorge, Jose and Francisco Mendoza were exhumed on Oct. 7 and turned over to their family.

Most of the farmworkers were from Morales, a city in the Caribbean province of Izabal, the judge said.

Los Zetas, which is led by Heriberto Lazcano Lazcano, known as "El Lazca," is considered Mexico's most violent drug cartel.

Lazcano deserted from the Mexican army in 1999 and formed Los Zetas with three other soldiers, all members of an elite special operations unit, becoming the armed wing of the Gulf drug cartel.

After several years on the payroll of the Gulf cartel, Los Zetas went into the drug business on their own account and now control several lucrative territories.